Working version of DataGridColumnsManager.py where columns can be updated

.claude/commands/unit-tester.md

@@ -258,7 +258,7 @@ def test_i_can_render_component_with_no_data(self, component):
 
 **Test order:**
 1. **First test:** Global structure (UTR-11.1)
-2. **Following tests:** Details of each section (UTR-11.2 to UTR-11.10)
+2. **Following tests:** Details of each section (UTR-11.2 to UTR-11.11)
 
 ---
 
@@ -410,8 +410,19 @@ expected = Div(style="width: 250px; overflow: hidden; display: flex;")
 
 **How to choose:**
 1. **Read the source code** to see how the icon is rendered
-2. If `mk.icon()` or equivalent wraps the icon in a Div → use `TestIcon()`
-3. If the icon is directly included without wrapper → use `TestIconNotStr()`
+2. If `mk.icon()` wraps the icon in a Div → use `TestIcon()` (default `wrapper="div"`)
+3. If `mk.label(..., icon=...)` wraps the icon in a Span → use `TestIcon(..., wrapper="span")`
+4. If the icon is directly included without wrapper → use `TestIconNotStr()`
+
+**The `wrapper` parameter:**
+
+Different `mk` helpers use different wrappers for icons:
+
+| Helper method | Wrapper element | TestIcon usage |
+|---------------|-----------------|----------------|
+| `mk.icon(my_icon)` | `<div>` | `TestIcon("name")` |
+| `mk.label("Text", icon=my_icon)` | `<span>` | `TestIcon("name", wrapper="span")` |
+| Direct: `Div(my_icon)` | none | `TestIconNotStr("name")` |
 
 **The `name` parameter:**
 - **Exact name**: Use the exact import name (e.g., `TestIcon("panel_right_expand20_regular")`) to validate a specific icon
@@ -420,25 +431,30 @@ expected = Div(style="width: 250px; overflow: hidden; display: flex;")
 **Examples:**
 
 ```python
-# Example 1: Wrapped icon (typically with mk.icon())
+# Example 1: Icon via mk.icon() - wrapper is Div (default)
 # Source code: mk.icon(panel_right_expand20_regular, size=20)
-# Rendered: <div><NotStr .../></div>
+# Rendered: <div><svg .../></div>
 expected = Header(
     Div(
-        TestIcon("panel_right_expand20_regular"),  # ✅ With wrapper
+        TestIcon("panel_right_expand20_regular"),  # ✅ wrapper="div" (default)
         cls=Contains("flex", "gap-1")
     )
 )
 
-# Example 2: Direct icon (used without helper)
+# Example 2: Icon via mk.label() - wrapper is Span
+# Source code: mk.label("Back", icon=chevron_left20_regular, command=...)
+# Rendered: <label><span><svg .../></span><span>Back</span></label>
+back_icon = find_one(details, TestIcon("chevron_left20_regular", wrapper="span"))  # ✅ wrapper="span"
+
+# Example 3: Direct icon (used without helper)
 # Source code: Span(dismiss_circle16_regular, cls="icon")
-# Rendered: <span><NotStr .../></span>
+# Rendered: <span><svg .../></span>
 expected = Span(
     TestIconNotStr("dismiss_circle16_regular"),  # ✅ Without wrapper
     cls=Contains("icon")
 )
 
-# Example 3: Verify any wrapped icon
+# Example 4: Verify any wrapped icon
 expected = Div(
     TestIcon(""),  # Accepts any wrapped icon
     cls=Contains("icon-wrapper")
@@ -446,7 +462,10 @@ expected = Div(
 ```
 
 **Debugging tip:**
-If your test fails with `TestIcon()`, try `TestIconNotStr()` and vice-versa. The error message will show you the actual structure.
+If your test fails with `TestIcon()`:
+1. Check if the wrapper is `<span>` instead of `<div>` → try `wrapper="span"`
+2. Check if there's no wrapper at all → try `TestIconNotStr()`
+3. The error message will show you the actual structure
 
 ---
 
@@ -467,11 +486,60 @@ expected = Script("(function() { const id = '...'; initResizer(id); })()")
 
 ---
 
+#### **UTR-11.9: Remove default `enctype` attribute when searching for Form elements**
+
+**Principle:** FastHTML's `Form()` component automatically adds `enctype="multipart/form-data"` as a default attribute. When using `find()` or `find_one()` to search for a Form, you must remove this attribute from the expected pattern.
+
+**Why:** The actual Form in your component may not have this attribute, causing the match to fail.
+
+**Problem:**
+```python
+# ❌ FAILS - Form() has default enctype that may not exist in actual form
+form = find_one(details, Form())  # AssertionError: Found 0 elements
+```
+
+**Solution:**
+```python
+# ✅ WORKS - Remove the default enctype attribute
+expected_form = Form()
+del expected_form.attrs["enctype"]
+form = find_one(details, expected_form)
+```
+
+**Alternative - Search with specific attribute:**
+```python
+# ✅ ALSO WORKS - Search by a known attribute
+form = find_one(details, Form(cls=Contains("my-form-class")))
+# But still need to delete enctype if Form() is used as pattern
+```
+
+**Complete example:**
+```python
+def test_column_details_contains_form(self, component):
+    """Test that column details contains a form with required fields."""
+    details = component.mk_column_details(col_def)
+
+    # Create Form pattern and remove default enctype
+    expected_form = Form()
+    del expected_form.attrs["enctype"]
+
+    form = find_one(details, expected_form)
+    assert form is not None
+
+    # Now search within the found form
+    title_input = find_one(form, Input(name="title"))
+    assert title_input is not None
+```
+
+**Note:** This is a FastHTML-specific behavior. Always check for similar default attributes when tests fail unexpectedly with "Found 0 elements".
+
+---
+
 ### **HOW TO DOCUMENT TESTS**
 
 ---
 
-#### **UTR-11.9: Justify the choice of tested elements**
+#### **UTR-11.10: Justify the choice of tested elements**
 
 **Principle:** In the test documentation section (after the description docstring), explain **why each tested element or attribute was chosen**. What makes it important for the functionality?
 
@@ -518,7 +586,7 @@ def test_left_drawer_is_rendered_when_open(self, layout):
 
 ---
 
-#### **UTR-11.10: Count tests with explicit messages**
+#### **UTR-11.11: Count tests with explicit messages**
 
 **Principle:** When you count elements with `assert len()`, ALWAYS add an explicit message explaining why this number is expected.
 
@@ -548,7 +616,7 @@ assert len(resizers) == 1
 2. **Documentation format**: Every render test MUST have a docstring with:
    - First line: Brief description of what is being tested
    - Blank line
-   - Justification section explaining why tested elements matter (see UTR-11.9)
+   - Justification section explaining why tested elements matter (see UTR-11.10)
    - List of important elements/attributes being tested with explanations (in English)
 
 3. **No inline comments**: Do NOT add comments on each line of the expected structure (except for structural clarification in global layout tests like `# left drawer`)
@@ -572,7 +640,7 @@ assert len(resizers) == 1
 
 ---
 
-#### **Summary: The 11 UTR-11 sub-rules**
+#### **Summary: The 12 UTR-11 sub-rules**
 
 **Prerequisite**
 - **UTR-11.0**: ⭐⭐⭐ Read `docs/testing_rendered_components.md` (MANDATORY)
@@ -590,10 +658,11 @@ assert len(resizers) == 1
 - **UTR-11.6**: Always `Contains()` for `cls` and `style`
 - **UTR-11.7**: `TestIcon()` or `TestIconNotStr()` to test icon presence
 - **UTR-11.8**: `TestScript()` for JavaScript
+- **UTR-11.9**: Remove default `enctype` from `Form()` patterns
 
 **How to document**
-- **UTR-11.9**: Justify the choice of tested elements
-- **UTR-11.10**: Explicit messages for `assert len()`
+- **UTR-11.10**: Justify the choice of tested elements
+- **UTR-11.11**: Explicit messages for `assert len()`
 
 ---
 
@@ -601,7 +670,7 @@ assert len(resizers) == 1
 - Reference specific patterns from the documentation
 - Explain why you chose to test certain elements and not others
 - Justify the use of predicates vs exact values
-- Always include justification documentation (see UTR-11.9)
+- Always include justification documentation (see UTR-11.10)
 
 ---
 

src/myfasthtml/assets/myfasthtml.css

@@ -59,6 +59,16 @@
  * Compatible with DaisyUI 5
  */
 
+.mf-button {
+    border-radius: 0.375rem;
+    transition: background-color 0.15s ease;
+}
+
+.mf-button:hover {
+    background-color: var(--color-base-300);
+}
+
+
 .mf-tooltip-container {
     background: var(--color-base-200);
     padding: 5px 10px;
@@ -1161,3 +1171,19 @@
 .dt2-moving {
     transition: transform 300ms ease;
 }
+
+/* *********************************************** */
+/* ******** DataGrid Column Manager ********** */
+/* *********************************************** */
+.dt2-column-manager-label {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    width: 100%;
+    border-radius: 0.375rem;
+    transition: background-color 0.15s ease;
+}
+
+.dt2-column-manager-label:hover {
+    background-color: var(--color-base-300);
+}

src/myfasthtml/assets/myfasthtml.js

@@ -1200,8 +1200,10 @@ function triggerHtmxAction(elementId, config, combinationStr, isInside, event) {
       }
     }
 
-    // Prevent default if we found any match and not in input context
-    if (currentMatches.length > 0 && !isInInputContext()) {
+    // Prevent default only if click was INSIDE a registered element
+    // Clicks outside should preserve native behavior (checkboxes, buttons, etc.)
+    const anyMatchInside = currentMatches.some(match => match.isInside);
+    if (currentMatches.length > 0 && anyMatchInside && !isInInputContext()) {
       event.preventDefault();
     }
 

src/myfasthtml/controls/DataGrid.py

@@ -17,7 +17,7 @@ from myfasthtml.controls.Mouse import Mouse
 from myfasthtml.controls.Panel import Panel, PanelConf
 from myfasthtml.controls.datagrid_objects import DataGridColumnState, DataGridRowState, \
   DatagridSelectionState, DataGridHeaderFooterConf, DatagridEditionState
-from myfasthtml.controls.helpers import mk
+from myfasthtml.controls.helpers import mk, icons
 from myfasthtml.core.commands import Command
 from myfasthtml.core.constants import ColumnType, ROW_INDEX_ID, FooterAggregation, DATAGRID_PAGE_SIZE, FILTER_INPUT_CID
 from myfasthtml.core.dbmanager import DbObject
@@ -138,6 +138,13 @@ class Commands(BaseCommands):
                    self._owner.toggle_columns_manager
                    ).htmx(target=None)
   
+  def on_column_changed(self):
+    return Command("OnColumnChanged",
+                   "Column definition changed",
+                   self._owner,
+                   self._owner.on_column_changed
+                   )
+
 
 class DataGrid(MultipleInstance):
   def __init__(self, parent, settings=None, save_state=None, _id=None):
@@ -170,6 +177,8 @@ class DataGrid(MultipleInstance):
     
     # add columns manager
     self._columns_manager = DataGridColumnsManager(self)
+    self._columns_manager.bind_command("ToggleColumn", self.commands.on_column_changed())
+    self._columns_manager.bind_command("UpdateColumn", self.commands.on_column_changed())
     
     # other definitions
     self._mouse_support = {
@@ -354,7 +363,7 @@ class DataGrid(MultipleInstance):
   def filter(self):
     logger.debug("filter")
     self._state.filtered[FILTER_INPUT_CID] = self._datagrid_filter.get_query()
-    return self.render_partial("body", redraw_scrollbars=True)
+    return self.render_partial("body")
   
   def on_click(self, combination, is_inside, cell_id):
     logger.debug(f"on_click {combination=} {is_inside=} {cell_id=}")
@@ -365,6 +374,10 @@ class DataGrid(MultipleInstance):
     
     return self.render_partial()
   
+  def on_column_changed(self):
+    logger.debug("on_column_changed")
+    return self.render_partial("table")
+  
   def change_selection_mode(self):
     logger.debug(f"change_selection_mode")
     new_state = self._selection_mode_selector.get_state()
@@ -377,17 +390,27 @@ class DataGrid(MultipleInstance):
     logger.debug(f"toggle_columns_manager")
     self._panel.set_right(self._columns_manager)
   
+  def save_state(self):
+    self._state.save()
+  
+  def get_state(self):
+    return self._state
+  
   def mk_headers(self):
     resize_cmd = self.commands.set_column_width()
     move_cmd = self.commands.move_column()
     
     def _mk_header_name(col_def: DataGridColumnState):
       return Div(
-        mk.label(col_def.title, name="dt2-header-title"),
+        mk.label(col_def.title, icon=icons.get(col_def.type, None)),
+        # make room for sort and filter indicators
         cls="flex truncate cursor-default",
       )
     
     def _mk_header(col_def: DataGridColumnState):
+      if not col_def.visible:
+        return None
+      
       return Div(
         _mk_header_name(col_def),
         Div(cls="dt2-resize-handle", data_command_id=resize_cmd.id),
@@ -397,7 +420,7 @@ class DataGrid(MultipleInstance):
         cls="dt2-cell dt2-resizable flex",
       )
     
-    header_class = "dt2-row dt2-header" + "" if self._settings.header_visible else " hidden"
+    header_class = "dt2-row dt2-header"
     return Div(
       *[_mk_header(col_def) for col_def in self._state.columns],
       cls=header_class,
@@ -470,7 +493,7 @@ class DataGrid(MultipleInstance):
       return None
     
     if not col_def.visible:
-      return OptimizedDiv(cls="dt2-col-hidden")
+      return None
     
     value = self._state.ns_fast_access[col_def.col_id][row_index]
     content = self.mk_body_cell_content(col_pos, row_index, col_def, filter_keyword_lower)
@@ -509,7 +532,7 @@ class DataGrid(MultipleInstance):
     
     return rows
   
-  def mk_body_container(self):
+  def mk_body_wrapper(self):
     return Div(
       self.mk_body(),
       cls="dt2-body-container",
@@ -535,28 +558,12 @@ class DataGrid(MultipleInstance):
       id=f"tf_{self._id}"
     )
   
-  def mk_table(self):
+  def mk_table_wrapper(self):
     return Div(
       self.mk_selection_manager(),
       
-      # Grid table with header, body, footer
-      Div(
-        # Header container - no scroll
-        Div(
-          self.mk_headers(),
-          cls="dt2-header-container"
-        ),
+      self.mk_table(),
       
-        self.mk_body_container(),  # Body container - scroll via JS, scrollbars hidden
-        
-        # Footer container - no scroll
-        Div(
-          self.mk_footers(),
-          cls="dt2-footer-container"
-        ),
-        cls="dt2-table",
-        id=f"t_{self._id}"
-      ),
       # Custom scrollbars overlaid
       Div(
         # Vertical scrollbar wrapper (right side)
@@ -575,6 +582,26 @@ class DataGrid(MultipleInstance):
       id=f"tw_{self._id}"
     )
   
+  def mk_table(self):
+    # Grid table with header, body, footer
+    return Div(
+      # Header container - no scroll
+      Div(
+        self.mk_headers(),
+        cls="dt2-header-container"
+      ),
+      
+      self.mk_body_wrapper(),  # Body container - scroll via JS, scrollbars hidden
+      
+      # Footer container - no scroll
+      Div(
+        self.mk_footers(),
+        cls="dt2-footer-container"
+      ),
+      cls="dt2-table",
+      id=f"t_{self._id}"
+    )
+  
   def mk_selection_manager(self):
     
     extra_attr = {
@@ -667,7 +694,7 @@ class DataGrid(MultipleInstance):
             mk.icon(settings16_regular, command=self.commands.toggle_columns_manager(), tooltip="Show sidebar"),
             cls="flex"),
           cls="flex items-center justify-between mb-2"),
-      self._panel.set_main(self.mk_table()),
+      self._panel.set_main(self.mk_table_wrapper()),
       Script(f"initDataGrid('{self._id}');"),
       Mouse(self, combinations=self._mouse_support),
       id=self._id,
@@ -675,7 +702,7 @@ class DataGrid(MultipleInstance):
       style="height: 100%; grid-template-rows: auto 1fr;"
     )
   
-  def render_partial(self, fragment="cell", redraw_scrollbars=False):
+  def render_partial(self, fragment="cell"):
     """
     
     :param fragment: cell | body
@@ -689,10 +716,15 @@ class DataGrid(MultipleInstance):
     }
     
     if fragment == "body":
-      body_container = self.mk_body_container()
+      body_container = self.mk_body_wrapper()
       body_container.attrs.update(extra_attr)
       res.append(body_container)
     
+    elif fragment == "table":
+      table = self.mk_table()
+      table.attrs.update(extra_attr)
+      res.append(table)
+    
     res.append(self.mk_selection_manager())
     
     return tuple(res)

src/myfasthtml/controls/DataGridColumnsManager.py

@@ -1,33 +1,190 @@
+import logging
+
 from fasthtml.components import *
 
+from myfasthtml.controls.BaseCommands import BaseCommands
 from myfasthtml.controls.Search import Search
 from myfasthtml.controls.datagrid_objects import DataGridColumnState
+from myfasthtml.controls.helpers import icons, mk
+from myfasthtml.core.commands import Command
+from myfasthtml.core.constants import ColumnType
 from myfasthtml.core.instances import MultipleInstance
+from myfasthtml.icons.fluent_p1 import chevron_right20_regular, chevron_left20_regular
+
+logger = logging.getLogger("DataGridColumnsManager")
+
+
+class Commands(BaseCommands):
+  def toggle_column(self, col_id):
+    return Command(f"ToggleColumn",
+                   f"Toggle column {col_id}",
+                   self._owner,
+                   self._owner.toggle_column,
+                   kwargs={"col_id": col_id}).htmx(swap="outerHTML", target=f"#tcolman_{self._id}-{col_id}")
+  
+  def show_column_details(self, col_id):
+    return Command(f"ShowColumnDetails",
+                   f"Show column details {col_id}",
+                   self._owner,
+                   self._owner.show_column_details,
+                   kwargs={"col_id": col_id}).htmx(target=f"#{self._id}", swap="innerHTML")
+  
+  def show_all_columns(self):
+    return Command(f"ShowAllColumns",
+                   f"Show all columns",
+                   self._owner,
+                   self._owner.show_all_columns).htmx(target=f"#{self._id}", swap="innerHTML")
+  
+  def update_column(self, col_id):
+    return Command(f"UpdateColumn",
+                   f"Update column {col_id}",
+                   self._owner,
+                   self._owner.update_column,
+                   kwargs={"col_id": col_id}
+                   ).htmx(target=f"#{self._id}", swap="innerHTML")
 
 
 class DataGridColumnsManager(MultipleInstance):
   def __init__(self, parent, _id=None):
     super().__init__(parent, _id=_id)
+    self.commands = Commands(self)
   
   @property
   def columns(self):
-    return self._parent._state.columns
+    return self._parent.get_state().columns
   
-  def mk_column(self, col_def: DataGridColumnState):
+  def _get_col_def_from_col_id(self, col_id):
+    cols_defs = [c for c in self.columns if c.col_id == col_id]
+    if not cols_defs:
+      return None
+    else:
+      return cols_defs[0]
+  
+  def toggle_column(self, col_id):
+    logger.debug(f"toggle_column {col_id=}")
+    col_def = self._get_col_def_from_col_id(col_id)
+    if col_def is None:
+      logger.debug(f"  column '{col_id}' is not found.")
+      return Div(f"Column '{col_id}' not found")
+    
+    col_def.visible = not col_def.visible
+    self._parent.save_state()
+    return self.mk_column_label(col_def)
+  
+  def show_column_details(self, col_id):
+    logger.debug(f"show_column_details {col_id=}")
+    col_def = self._get_col_def_from_col_id(col_id)
+    if col_def is None:
+      logger.debug(f"  column '{col_id}' is not found.")
+      return Div(f"Column '{col_id}' not found")
+    
+    return self.mk_column_details(col_def)
+  
+  def show_all_columns(self):
+    return self.mk_all_columns()
+  
+  def update_column(self, col_id, client_response):
+    logger.debug(f"update_column {col_id=}, {client_response=}")
+    col_def = self._get_col_def_from_col_id(col_id)
+    if col_def is None:
+      logger.debug(f"  column '{col_id}' is not found.")
+    else:
+      for k, v in client_response.items():
+        if not hasattr(col_def, k):
+          continue
+        
+        if k == "visible":
+          col_def.visible = v == "on"
+        elif k == "type":
+          col_def.type = ColumnType(v)
+        elif k == "width":
+          col_def.width = int(v)
+        else:
+          setattr(col_def, k, v)
+        
+        # save the new values
+        self._parent.save_state()
+    
+    return self.mk_all_columns()
+  
+  def mk_column_label(self, col_def: DataGridColumnState):
     return Div(
-      Input(type="checkbox", checked=col_def.visible, cls="ml-2"),
-      Label(col_def.col_id, cls="ml-2"),
-      cls="flex mb-1",
+      mk.mk(
+        Input(type="checkbox", cls="checkbox checkbox-sm", checked=col_def.visible),
+        command=self.commands.toggle_column(col_def.col_id)
+      ),
+      mk.mk(
+        Div(
+          Div(mk.label(col_def.col_id, icon=icons.get(col_def.type, None), cls="ml-2")),
+          Div(mk.icon(chevron_right20_regular), cls="mr-2"),
+          cls="dt2-column-manager-label"
+        ),
+        command=self.commands.show_column_details(col_def.col_id)
+      ),
+      cls="flex mb-1 items-center",
+      id=f"tcolman_{self._id}-{col_def.col_id}"
     )
   
-  def render(self):
+  def mk_column_details(self, col_def: DataGridColumnState):
+    size = "sm"
+    return Div(
+      mk.label("Back", icon=chevron_left20_regular, command=self.commands.show_all_columns()),
+      Form(
+        Fieldset(
+          Label("Column Id"),
+          Input(name="col_id",
+                cls=f"input input-{size}",
+                value=col_def.col_id,
+                readonly=True),
+          
+          Label("Title"),
+          Input(name="title",
+                cls=f"input input-{size}",
+                value=col_def.title),
+          
+          Label("Visible"),
+          Input(name="visible",
+                type="checkbox",
+                cls=f"checkbox checkbox-{size}",
+                checked="true" if col_def.visible else None),
+          
+          Label("type"),
+          Select(
+            *[Option(option.value, value=option.value, selected=option == col_def.type) for option in ColumnType],
+            name="type",
+            cls=f"select select-{size}",
+            value=col_def.title,
+          ),
+          
+          Label("Width"),
+          Input(name="width",
+                type="number",
+                cls=f"input input-{size}",
+                value=col_def.width),
+          
+          legend="Column details",
+          cls="fieldset border-base-300 rounded-box"
+        ),
+        mk.dialog_buttons(on_ok=self.commands.update_column(col_def.col_id),
+                          on_cancel=self.commands.show_all_columns()),
+        cls="mb-1",
+      ),
+    )
+  
+  def mk_all_columns(self):
     return Search(self,
                   items_names="Columns",
                   items=self.columns,
                   get_attr=lambda x: x.col_id,
-                  template=self.mk_column,
+                  template=self.mk_column_label,
                   max_height=None
                   )
   
+  def render(self):
+    return Div(
+      self.mk_all_columns(),
+      id=self._id,
+    )
+  
   def __ft__(self):
     return self.render()

src/myfasthtml/controls/helpers.py

@@ -2,7 +2,14 @@ from fasthtml.components import *
 
 from myfasthtml.core.bindings import Binding
 from myfasthtml.core.commands import Command, CommandTemplate
+from myfasthtml.core.constants import ColumnType
 from myfasthtml.core.utils import merge_classes
+from myfasthtml.icons.fluent import question20_regular, brain_circuit20_regular, number_row20_regular, \
+  number_symbol20_regular
+from myfasthtml.icons.fluent_p1 import checkbox_checked20_regular, checkbox_unchecked20_regular, \
+  checkbox_checked20_filled
+from myfasthtml.icons.fluent_p2 import text_bullet_list_square20_regular, text_field20_regular
+from myfasthtml.icons.fluent_p3 import calendar_ltr20_regular
 
 
 class Ids:
@@ -96,7 +103,7 @@ class mk:
             command: Command | CommandTemplate = None,
             binding: Binding = None,
             **kwargs):
-    merged_cls = merge_classes("flex truncate", cls, kwargs)
+    merged_cls = merge_classes("flex truncate items-center", "mf-button" if command else None, cls, kwargs)
     icon_part = Span(icon, cls=f"mf-icon-{mk.convert_size(size)} mr-1") if icon else None
     text_part = Span(text, cls=f"text-{size}")
     return mk.mk(Label(icon_part, text_part, cls=merged_cls, **kwargs), command=command, binding=binding)
@@ -138,3 +145,19 @@ class mk:
     ft = mk.manage_command(ft, command) if command else ft
     ft = mk.manage_binding(ft, binding, init_binding=init_binding) if binding else ft
     return ft
+
+
+icons = {
+    None: question20_regular,
+    True: checkbox_checked20_regular,
+    False: checkbox_unchecked20_regular,
+    
+    "Brain": brain_circuit20_regular,
+    
+    ColumnType.RowIndex: number_symbol20_regular,
+    ColumnType.Text: text_field20_regular,
+    ColumnType.Number: number_row20_regular,
+    ColumnType.Datetime: calendar_ltr20_regular,
+    ColumnType.Bool: checkbox_checked20_filled,
+    ColumnType.List: text_bullet_list_square20_regular,
+}

src/myfasthtml/test/matcher.py

@@ -186,8 +186,9 @@ class TestObject:
 
 
 class TestIcon(TestObject):
-  def __init__(self, name: Optional[str] = '', command=None):
-    super().__init__("div")
+  def __init__(self, name: Optional[str] = '', wrapper="div", command=None):
+    super().__init__(wrapper)
+    self.wrapper = wrapper
     self.name = snake_to_pascal(name) if (name and name[0].islower()) else name
     self.children = [
         TestObject(NotStr, s=Regex(f'<svg name="\\w+-{self.name}'))
@@ -196,7 +197,7 @@ class TestIcon(TestObject):
       self.attrs |= command.get_htmx_params()
   
   def __str__(self):
-    return f'<div><svg name="{self.name}" .../></div>'
+    return f'<{self.wrapper}><svg name="{self.name}" .../></{self.wrapper}>'
 
 
 class TestIconNotStr(TestObject):

tests/controls/test_datagrid_columns_manager.py

@@ -0,0 +1,469 @@
+import shutil
+from dataclasses import dataclass, field
+from unittest.mock import Mock
+
+import pytest
+from fasthtml.common import Div, Input, Label, Form, Fieldset, Select
+
+from myfasthtml.controls.DataGridColumnsManager import DataGridColumnsManager, Commands
+from myfasthtml.controls.Search import Search
+from myfasthtml.controls.datagrid_objects import DataGridColumnState
+from myfasthtml.core.constants import ColumnType
+from myfasthtml.core.instances import InstancesManager, MultipleInstance
+from myfasthtml.test.matcher import (
+    matches, find_one, find, Contains, TestIcon, TestObject
+)
+
+
+@dataclass
+class MockDatagridState:
+    """Mock state object that mimics DatagridState."""
+    columns: list = field(default_factory=list)
+
+
+class MockDataGrid(MultipleInstance):
+    """Mock DataGrid parent for testing DataGridColumnsManager."""
+
+    def __init__(self, parent, columns=None, _id=None):
+        super().__init__(parent, _id=_id)
+        self._state = MockDatagridState(columns=columns or [])
+        self._save_state_called = False
+
+    def get_state(self):
+        return self._state
+
+    def save_state(self):
+        self._save_state_called = True
+
+
+@pytest.fixture
+def mock_datagrid(root_instance):
+    """Create a mock DataGrid with sample columns."""
+    columns = [
+        DataGridColumnState(col_id="name", col_index=0, title="Name", type=ColumnType.Text, visible=True),
+        DataGridColumnState(col_id="age", col_index=1, title="Age", type=ColumnType.Number, visible=True),
+        DataGridColumnState(col_id="email", col_index=2, title="Email", type=ColumnType.Text, visible=False),
+    ]
+    yield MockDataGrid(root_instance, columns=columns, _id="test-datagrid")
+    InstancesManager.reset()
+
+
+@pytest.fixture
+def columns_manager(mock_datagrid):
+    """Create a DataGridColumnsManager instance for testing."""
+    shutil.rmtree(".myFastHtmlDb", ignore_errors=True)
+    yield DataGridColumnsManager(mock_datagrid)
+    shutil.rmtree(".myFastHtmlDb", ignore_errors=True)
+
+
+class TestDataGridColumnsManagerBehaviour:
+    """Tests for DataGridColumnsManager behavior and logic."""
+
+    # =========================================================================
+    # Initialization
+    # =========================================================================
+
+    def test_i_can_create_columns_manager(self, mock_datagrid):
+        """Test that DataGridColumnsManager can be created with a DataGrid parent."""
+        cm = DataGridColumnsManager(mock_datagrid)
+
+        assert cm is not None
+        assert cm._parent == mock_datagrid
+        assert isinstance(cm.commands, Commands)
+
+    # =========================================================================
+    # Columns Property
+    # =========================================================================
+
+    def test_columns_property_returns_parent_state_columns(self, columns_manager, mock_datagrid):
+        """Test that columns property returns columns from parent's state."""
+        columns = columns_manager.columns
+
+        assert columns == mock_datagrid.get_state().columns
+        assert len(columns) == 3
+        assert columns[0].col_id == "name"
+
+    # =========================================================================
+    # Get Column Definition
+    # =========================================================================
+
+    def test_i_can_get_existing_column_by_id(self, columns_manager):
+        """Test finding an existing column by its ID."""
+        col_def = columns_manager._get_col_def_from_col_id("name")
+
+        assert col_def is not None
+        assert col_def.col_id == "name"
+        assert col_def.title == "Name"
+
+    def test_i_cannot_get_nonexistent_column(self, columns_manager):
+        """Test that getting a nonexistent column returns None."""
+        col_def = columns_manager._get_col_def_from_col_id("nonexistent")
+
+        assert col_def is None
+
+    # =========================================================================
+    # Toggle Column Visibility
+    # =========================================================================
+
+    @pytest.mark.parametrize("col_id, initial_visible, expected_visible", [
+        ("name", True, False),   # visible -> hidden
+        ("email", False, True),  # hidden -> visible
+    ])
+    def test_i_can_toggle_column_visibility(self, columns_manager, col_id, initial_visible, expected_visible):
+        """Test toggling column visibility from visible to hidden and vice versa."""
+        col_def = columns_manager._get_col_def_from_col_id(col_id)
+        assert col_def.visible == initial_visible
+
+        columns_manager.toggle_column(col_id)
+
+        assert col_def.visible == expected_visible
+
+    def test_toggle_column_saves_state(self, columns_manager, mock_datagrid):
+        """Test that toggle_column calls save_state on parent."""
+        mock_datagrid._save_state_called = False
+
+        columns_manager.toggle_column("name")
+
+        assert mock_datagrid._save_state_called is True
+
+    def test_toggle_column_returns_column_label(self, columns_manager):
+        """Test that toggle_column returns the updated column label."""
+        result = columns_manager.toggle_column("name")
+
+        # Result should be a Div with the column label structure
+        assert result is not None
+        assert hasattr(result, 'tag')
+
+    def test_i_cannot_toggle_nonexistent_column(self, columns_manager):
+        """Test that toggling a nonexistent column returns an error message."""
+        result = columns_manager.toggle_column("nonexistent")
+
+        expected = Div("Column 'nonexistent' not found")
+        assert matches(result, expected)
+
+    # =========================================================================
+    # Show Column Details
+    # =========================================================================
+
+    def test_i_can_show_column_details_for_existing_column(self, columns_manager):
+        """Test that show_column_details returns the details form for an existing column."""
+        result = columns_manager.show_column_details("name")
+
+        # Should contain a Form - check by finding form tag in children
+        expected = Form()
+        del(expected.attrs["enctype"]) # hack. We don't know why enctype is added
+        forms = find(result, expected)
+        assert len(forms) == 1, "Should contain exactly one form"
+
+    def test_i_cannot_show_details_for_nonexistent_column(self, columns_manager):
+        """Test that showing details for nonexistent column returns error message."""
+        result = columns_manager.show_column_details("nonexistent")
+
+        expected = Div("Column 'nonexistent' not found")
+        assert matches(result, expected)
+
+    # =========================================================================
+    # Show All Columns
+    # =========================================================================
+
+    def test_show_all_columns_returns_search_component(self, columns_manager):
+        """Test that show_all_columns returns a Search component."""
+        result = columns_manager.show_all_columns()
+
+        assert isinstance(result, Search)
+
+    def test_show_all_columns_contains_all_columns(self, columns_manager):
+        """Test that show_all_columns Search contains all columns."""
+        result = columns_manager.show_all_columns()
+
+        assert len(result.items) == 3
+
+    # =========================================================================
+    # Update Column
+    # =========================================================================
+
+    def test_i_can_update_column_title(self, columns_manager):
+        """Test updating a column's title via client_response."""
+        client_response = {"title": "New Name"}
+
+        columns_manager.update_column("name", client_response)
+
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        assert col_def.title == "New Name"
+
+    def test_i_can_update_column_visibility_via_form(self, columns_manager):
+        """Test updating column visibility via checkbox form value."""
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        assert col_def.visible is True
+
+        # Unchecked checkbox sends nothing, checked sends "on"
+        client_response = {"visible": "off"}  # Not "on" means unchecked
+        columns_manager.update_column("name", client_response)
+
+        assert col_def.visible is False
+
+        # Check it back on
+        client_response = {"visible": "on"}
+        columns_manager.update_column("name", client_response)
+
+        assert col_def.visible is True
+
+    def test_i_can_update_column_type(self, columns_manager):
+        """Test updating a column's type."""
+        client_response = {"type": "Number"}
+
+        columns_manager.update_column("name", client_response)
+
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        assert col_def.type == ColumnType.Number
+
+    def test_i_can_update_column_width(self, columns_manager):
+        """Test updating a column's width."""
+        client_response = {"width": "200"}
+
+        columns_manager.update_column("name", client_response)
+
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        assert col_def.width == 200
+
+    def test_update_column_saves_state(self, columns_manager, mock_datagrid):
+        """Test that update_column calls save_state on parent."""
+        mock_datagrid._save_state_called = False
+
+        columns_manager.update_column("name", {"title": "Updated"})
+
+        assert mock_datagrid._save_state_called is True
+
+    def test_update_column_ignores_unknown_attributes(self, columns_manager):
+        """Test that update_column ignores attributes not in DataGridColumnState."""
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        original_title = col_def.title
+
+        client_response = {"unknown_attr": "value", "title": "New Title"}
+        columns_manager.update_column("name", client_response)
+
+        # unknown_attr should be ignored, title should be updated
+        assert col_def.title == "New Title"
+        assert not hasattr(col_def, "unknown_attr")
+
+    def test_i_cannot_update_nonexistent_column(self, columns_manager):
+        """Test that updating nonexistent column returns mk_all_columns result."""
+        result = columns_manager.update_column("nonexistent", {"title": "Test"})
+
+        # Should return the all columns view (Search component)
+        assert isinstance(result, Search)
+
+
+class TestDataGridColumnsManagerRender:
+    """Tests for DataGridColumnsManager HTML rendering."""
+
+    @pytest.fixture
+    def columns_manager(self, mock_datagrid):
+        """Create a fresh DataGridColumnsManager for render tests."""
+        shutil.rmtree(".myFastHtmlDb", ignore_errors=True)
+        cm = DataGridColumnsManager(mock_datagrid)
+        yield cm
+        shutil.rmtree(".myFastHtmlDb", ignore_errors=True)
+
+    # =========================================================================
+    # Global Structure
+    # =========================================================================
+
+    def test_i_can_render_columns_manager_with_columns(self, columns_manager):
+        """Test that DataGridColumnsManager renders with correct global structure.
+
+        Why these elements matter:
+        - id: Required for HTMX targeting in commands
+        - Contains Search component: Main content for column list
+        """
+        html = columns_manager.render()
+
+        expected = Div(
+            TestObject(Search),  # Search component
+            id=columns_manager._id,
+        )
+
+        assert matches(html, expected)
+
+    # =========================================================================
+    # mk_column_label
+    # =========================================================================
+
+    def test_column_label_has_checkbox_and_details_navigation(self, columns_manager):
+        """Test that column label contains checkbox and navigation to details.
+
+        Why these elements matter:
+        - Checkbox (Input type=checkbox): Controls column visibility
+        - Label with column ID: Identifies the column
+        - Chevron icon: Indicates navigation to details
+        - id with tcolman_ prefix: Required for HTMX swap targeting
+        """
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        label = columns_manager.mk_column_label(col_def)
+
+        # Should have the correct ID pattern
+        expected = Div(
+            id=f"tcolman_{columns_manager._id}-name",
+            cls=Contains("flex"),
+        )
+        assert matches(label, expected)
+
+        # Should contain a checkbox
+        checkbox = find_one(label, Input(type="checkbox"))
+        assert checkbox is not None
+
+        # Should contain chevron icon for navigation
+        chevron = find_one(label, TestIcon("chevron_right20_regular"))
+        assert chevron is not None
+
+    def test_column_label_checkbox_is_checked_when_visible(self, columns_manager):
+        """Test that checkbox is checked when column is visible.
+
+        Why this matters:
+        - checked attribute: Reflects current visibility state
+        - User can see which columns are visible
+        """
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        assert col_def.visible is True
+
+        label = columns_manager.mk_column_label(col_def)
+        checkbox = find_one(label, Input(type="checkbox"))
+
+        # Checkbox should have checked attribute
+        assert checkbox.attrs.get("checked") is True
+
+    def test_column_label_checkbox_is_unchecked_when_hidden(self, columns_manager):
+        """Test that checkbox is unchecked when column is hidden.
+
+        Why this matters:
+        - No checked attribute: Indicates column is hidden
+        - Visual feedback for user
+        """
+        col_def = columns_manager._get_col_def_from_col_id("email")
+        assert col_def.visible is False
+
+        label = columns_manager.mk_column_label(col_def)
+        checkbox = find_one(label, Input(type="checkbox"))
+
+        # Checkbox should not have checked attribute (or it should be False/None)
+        checked = checkbox.attrs.get("checked")
+        assert checked is None or checked is False
+
+    # =========================================================================
+    # mk_column_details
+    # =========================================================================
+
+    def test_column_details_contains_all_form_fields(self, columns_manager):
+        """Test that column details form contains all required fields.
+
+        Why these elements matter:
+        - col_id field (readonly): Shows column identifier
+        - title field: Editable column display name
+        - visible checkbox: Toggle visibility
+        - type select: Change column type
+        - width input: Set column width
+        """
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        details = columns_manager.mk_column_details(col_def)
+
+        # Should contain Form
+        form = Form()
+        del form.attrs["enctype"]
+        form = find_one(details, form)
+        assert form is not None
+
+        # Should contain all required input fields
+        col_id_input = find_one(form, Input(name="col_id"))
+        assert col_id_input is not None
+        assert col_id_input.attrs.get("readonly") is True
+
+        title_input = find_one(form, Input(name="title"))
+        assert title_input is not None
+
+        visible_checkbox = find_one(form, Input(name="visible", type="checkbox"))
+        assert visible_checkbox is not None
+
+        type_select = find_one(form, Select(name="type"))
+        assert type_select is not None
+
+        width_input = find_one(form, Input(name="width", type="number"))
+        assert width_input is not None
+
+    def test_column_details_has_back_button(self, columns_manager):
+        """Test that column details has a back button to return to all columns.
+
+        Why this matters:
+        - Back navigation: User can return to column list
+        - Chevron left icon: Visual indicator of back action
+        """
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        details = columns_manager.mk_column_details(col_def)
+
+        # Should contain back chevron icon
+        back_icon = find_one(details, TestIcon("chevron_left20_regular", wrapper="span"))
+        assert back_icon is not None
+
+    def test_column_details_form_has_fieldset_with_legend(self, columns_manager):
+        """Test that column details form has a fieldset with legend.
+
+        Why this matters:
+        - Fieldset groups related fields
+        - Legend provides context ("Column details")
+        """
+        col_def = columns_manager._get_col_def_from_col_id("name")
+        details = columns_manager.mk_column_details(col_def)
+
+        fieldset = find_one(details, Fieldset(legend="Column details"))
+        assert fieldset is not None
+
+    # =========================================================================
+    # mk_all_columns
+    # =========================================================================
+
+    def test_all_columns_uses_search_component(self, columns_manager):
+        """Test that mk_all_columns returns a Search component.
+
+        Why this matters:
+        - Search component: Enables filtering columns by name
+        - items_names="Columns": Labels the search appropriately
+        """
+        result = columns_manager.mk_all_columns()
+
+        assert isinstance(result, Search)
+        assert result.items_names == "Columns"
+
+    def test_all_columns_search_has_correct_configuration(self, columns_manager):
+        """Test that Search component is configured correctly.
+
+        Why these elements matter:
+        - items: Contains all column definitions
+        - get_attr: Extracts col_id for search matching
+        - template: Uses mk_column_label for rendering
+        """
+        result = columns_manager.mk_all_columns()
+
+        # Should have all 3 columns
+        assert len(result.items) == 3
+
+        # get_attr should return col_id
+        col_def = result.items[0]
+        assert result.get_attr(col_def) == col_def.col_id
+
+    def test_all_columns_renders_all_column_labels(self, columns_manager):
+        """Test that all columns render produces labels for all columns.
+
+        Why this matters:
+        - All columns visible in list
+        - Each column has its label rendered
+        """
+        search = columns_manager.mk_all_columns()
+        rendered = search.render()
+
+        # Should find 3 column labels in the results
+        results_div = find_one(rendered, Div(id=f"{search._id}-results"))
+        assert results_div is not None
+
+        # Each column should have a label with tcolman_ prefix
+        for col_id in ["name", "age", "email"]:
+            label = find_one(results_div, Div(id=f"tcolman_{columns_manager._id}-{col_id}"))
+            assert label is not None, f"Column label for '{col_id}' should be present"