Added mouse selection

src/myfasthtml/assets/core/mouse.js

@@ -14,7 +14,15 @@
     pendingMatches: [], // Array of matches waiting for timeout
     sequenceTimeout: 500, // 500ms timeout for sequences
     clickHandler: null,
-    contextmenuHandler: null
+    contextmenuHandler: null,
+    mousedownState: null,       // Active drag state (only after movement detected)
+    suppressNextClick: false,   // Prevents click from firing after mousedown>mouseup
+    mousedownHandler: null,     // Handler reference for cleanup
+    mouseupHandler: null,       // Handler reference for cleanup
+    mousedownSafetyTimeout: null, // Safety timeout if mouseup never arrives
+    mousedownPending: null,     // Pending mousedown data (before movement detected)
+    mousemoveHandler: null,     // Handler for detecting drag movement
+    dragThreshold: 5            // Minimum pixels to consider it a drag (not a click)
   };
 
   /**
@@ -33,6 +41,58 @@
     return aliasMap[normalized] || normalized;
   }
 
+  /**
+   * Check if an action Set contains a mousedown>mouseup action
+   * @param {Set} actionSet - Set of normalized actions
+   * @returns {boolean} - True if contains mousedown>mouseup or rmousedown>mouseup
+   */
+  function isMousedownUpAction(actionSet) {
+    return actionSet.has('mousedown>mouseup') || actionSet.has('rmousedown>mouseup');
+  }
+
+  /**
+   * Get the expected mouse button for a mousedown>mouseup action
+   * @param {Set} actionSet - Set of normalized actions
+   * @returns {number} - 0 for left button, 2 for right button
+   */
+  function getMousedownUpButton(actionSet) {
+    return actionSet.has('rmousedown>mouseup') ? 2 : 0;
+  }
+
+  /**
+   * Scan all registered element trees to find mousedown>mouseup candidates
+   * that are the next expected step given the current snapshot history.
+   * @param {Array} snapshotHistory - Current snapshot history
+   * @returns {Array} - Array of { elementId, node, actionSet, button } candidates
+   */
+  function checkTreesForMousedownUp(snapshotHistory) {
+    const candidates = [];
+
+    for (const [elementId, data] of MouseRegistry.elements) {
+      const element = document.getElementById(elementId);
+      if (!element) continue;
+
+      // Traverse tree to current position in history
+      const currentNode = traverseTree(data.tree, snapshotHistory);
+      if (!currentNode) continue;
+
+      // Check children for mousedown>mouseup actions
+      for (const [key, childNode] of currentNode.children) {
+        const actionSet = new Set(key.split('+'));
+        if (isMousedownUpAction(actionSet)) {
+          candidates.push({
+            elementId: elementId,
+            node: childNode,
+            actionSet: actionSet,
+            button: getMousedownUpButton(actionSet)
+          });
+        }
+      }
+    }
+
+    return candidates;
+  }
+
   /**
    * Create a unique string key from a Set of actions for Map indexing
    * @param {Set} actionSet - Set of normalized actions
@@ -226,6 +286,16 @@
    * @param {MouseEvent} event - The mouse event
    */
   function handleGlobalClick(event) {
+    // Suppress click that fires after mousedown>mouseup drag
+    if (MouseRegistry.suppressNextClick) {
+      MouseRegistry.suppressNextClick = false;
+      return;
+    }
+
+    // Don't process clicks during active drag mode (movement detected)
+    // But DO process clicks if only mousedownPending (no movement = normal click)
+    if (MouseRegistry.mousedownState) return;
+
     // DEBUG: Measure click handler performance
     const clickStart = performance.now();
     const elementCount = MouseRegistry.elements.size;
@@ -362,6 +432,10 @@
    * @param {MouseEvent} event - The mouse event
    */
   function handleElementRightClick(event) {
+    // Don't process right-clicks during active drag with right button
+    // But DO process if only pending (no movement = normal right-click)
+    if (MouseRegistry.mousedownState && MouseRegistry.mousedownState.button === 2) return;
+
     // Find which registered element was clicked
     const elementId = findRegisteredElement(event.target);
 
@@ -489,6 +563,400 @@
     }
   }
 
+  /**
+   * Clean up mousedown state and safety timeout
+   */
+  function clearMousedownState() {
+    if (MouseRegistry.mousedownSafetyTimeout) {
+      clearTimeout(MouseRegistry.mousedownSafetyTimeout);
+      MouseRegistry.mousedownSafetyTimeout = null;
+    }
+
+    // Remove mousemove listener if attached
+    if (MouseRegistry.mousemoveHandler) {
+      document.removeEventListener('mousemove', MouseRegistry.mousemoveHandler);
+      MouseRegistry.mousemoveHandler = null;
+    }
+
+    MouseRegistry.mousedownState = null;
+    MouseRegistry.mousedownPending = null;
+  }
+
+  /**
+   * Handle global mousedown events for mousedown>mouseup actions.
+   * Stores pending state and waits for movement to activate drag mode.
+   * @param {MouseEvent} event - The mousedown event
+   */
+  function handleMouseDown(event) {
+    // Exit early if already in mousedown state or pending
+    if (MouseRegistry.mousedownState || MouseRegistry.mousedownPending) return;
+
+    // Check if any registered tree has a mousedown>mouseup action as the next step
+    const candidates = checkTreesForMousedownUp(MouseRegistry.snapshotHistory);
+    if (candidates.length === 0) return;
+
+    // Filter candidates by button match
+    const matchingCandidates = candidates.filter(c => c.button === event.button);
+    if (matchingCandidates.length === 0) return;
+
+    // Check if mousedown target is inside any registered element
+    const hasFocusMap = {};
+    for (const candidate of matchingCandidates) {
+      const element = document.getElementById(candidate.elementId);
+      if (element) {
+        hasFocusMap[candidate.elementId] = document.activeElement === element;
+      }
+    }
+
+    // Store PENDING mousedown state (not activated yet)
+    MouseRegistry.mousedownPending = {
+      button: event.button,
+      ctrlKey: event.ctrlKey || event.metaKey,
+      shiftKey: event.shiftKey,
+      altKey: event.altKey,
+      startX: event.clientX,
+      startY: event.clientY,
+      mousedownEvent: event,
+      hasFocusMap: hasFocusMap,
+      candidates: matchingCandidates
+    };
+
+    // Add mousemove listener to detect drag
+    MouseRegistry.mousemoveHandler = (moveEvent) => {
+      if (!MouseRegistry.mousedownPending) return;
+
+      const deltaX = Math.abs(moveEvent.clientX - MouseRegistry.mousedownPending.startX);
+      const deltaY = Math.abs(moveEvent.clientY - MouseRegistry.mousedownPending.startY);
+
+      // If moved beyond threshold, activate drag mode
+      if (deltaX > MouseRegistry.dragThreshold || deltaY > MouseRegistry.dragThreshold) {
+        activateDragMode(MouseRegistry.mousedownPending);
+      }
+    };
+    document.addEventListener('mousemove', MouseRegistry.mousemoveHandler);
+
+    // Safety timeout: clean up if mouseup never arrives (5 seconds)
+    MouseRegistry.mousedownSafetyTimeout = setTimeout(() => {
+      clearMousedownState();
+    }, 5000);
+  }
+
+  /**
+   * Activate drag mode after movement detected.
+   * Called by mousemove handler when threshold exceeded.
+   * @param {Object} pendingData - The pending mousedown data
+   */
+  function activateDragMode(pendingData) {
+    if (!pendingData) return;
+
+    const event = pendingData.mousedownEvent;
+
+    // Suspend sequence timeout (keep pendingMatches but stop the timer)
+    if (MouseRegistry.pendingTimeout) {
+      clearTimeout(MouseRegistry.pendingTimeout);
+      MouseRegistry.pendingTimeout = null;
+    }
+
+    // Call hx-vals-extra JS functions at mousedown time, suffix results with _mousedown
+    const mousedownJsValues = {};
+    for (const candidate of pendingData.candidates) {
+      const config = candidate.node.config;
+      if (!config) continue;
+
+      const extra = config['hx-vals-extra'];
+      if (extra && extra.js) {
+        try {
+          const func = window[extra.js];
+          if (typeof func === 'function') {
+            const element = document.getElementById(candidate.elementId);
+            const dynamicValues = func(event, element, candidate.node.combinationStr);
+            if (dynamicValues && typeof dynamicValues === 'object') {
+              // Suffix each key with _mousedown
+              const suffixed = {};
+              for (const [key, value] of Object.entries(dynamicValues)) {
+                suffixed[key + '_mousedown'] = value;
+              }
+              mousedownJsValues[candidate.elementId] = suffixed;
+            }
+          }
+        } catch (e) {
+          console.error('Error calling dynamic hx-vals function at mousedown:', e);
+        }
+      }
+    }
+
+    // Activate drag state
+    MouseRegistry.mousedownState = {
+      button: pendingData.button,
+      ctrlKey: pendingData.ctrlKey,
+      shiftKey: pendingData.shiftKey,
+      altKey: pendingData.altKey,
+      hasFocusMap: pendingData.hasFocusMap,
+      candidates: pendingData.candidates,
+      mousedownJsValues: mousedownJsValues
+    };
+
+    // Clear pending state
+    MouseRegistry.mousedownPending = null;
+
+    // Remove mousemove listener (no longer needed)
+    if (MouseRegistry.mousemoveHandler) {
+      document.removeEventListener('mousemove', MouseRegistry.mousemoveHandler);
+      MouseRegistry.mousemoveHandler = null;
+    }
+
+    // For right button: prevent context menu during drag
+    if (pendingData.button === 2) {
+      const preventContextMenu = (e) => {
+        e.preventDefault();
+      };
+      document.addEventListener('contextmenu', preventContextMenu, { capture: true, once: true });
+    }
+
+    // Prevent default if on a registered element and not in input context
+    const targetElementId = findRegisteredElement(event.target);
+    if (targetElementId && !isInInputContext()) {
+      event.preventDefault();
+    }
+  }
+
+  /**
+   * Handle global mouseup events for mousedown>mouseup actions.
+   * Resolves the mousedown>mouseup action when mouseup fires (only if drag was activated).
+   * @param {MouseEvent} event - The mouseup event
+   */
+  function handleMouseUp(event) {
+    // Case 1: Drag mode was activated (movement detected)
+    if (MouseRegistry.mousedownState) {
+      const mdState = MouseRegistry.mousedownState;
+
+      // Verify button matches mousedown button
+      if (event.button !== mdState.button) return;
+
+      // Build action name based on button
+      const actionName = mdState.button === 2 ? 'rmousedown>mouseup' : 'mousedown>mouseup';
+
+      // Build snapshot Set with modifiers from mousedown time
+      const snapshot = new Set([actionName]);
+      if (mdState.ctrlKey) snapshot.add('ctrl');
+      if (mdState.shiftKey) snapshot.add('shift');
+      if (mdState.altKey) snapshot.add('alt');
+
+      // Add snapshot to history
+      MouseRegistry.snapshotHistory.push(snapshot);
+
+      // Clear mousedown state
+      clearMousedownState();
+
+      // Suppress next click for left button (click fires after mouseup)
+      if (mdState.button === 0) {
+        MouseRegistry.suppressNextClick = true;
+      }
+
+      // Resolve with tree-traversal matching
+      resolveAfterMouseUp(event, mdState);
+      return;
+    }
+
+    // Case 2: Mousedown pending but no movement (it's a click, not a drag)
+    if (MouseRegistry.mousedownPending) {
+      const pending = MouseRegistry.mousedownPending;
+
+      // Verify button matches
+      if (event.button !== pending.button) return;
+
+      // Clean up pending state - let the normal click handler process it
+      clearMousedownState();
+      // Don't suppress click - we want it to fire normally
+      return;
+    }
+  }
+
+  /**
+   * Resolve mousedown>mouseup action using tree-traversal matching.
+   * Same logic as handleGlobalClick but uses triggerMousedownUpAction.
+   * @param {MouseEvent} mouseupEvent - The mouseup event
+   * @param {Object} mdState - The mousedown state captured earlier
+   */
+  function resolveAfterMouseUp(mouseupEvent, mdState) {
+    const currentMatches = [];
+    let anyHasLongerSequence = false;
+    let foundAnyMatch = false;
+
+    for (const [elementId, data] of MouseRegistry.elements) {
+      const element = document.getElementById(elementId);
+      if (!element) continue;
+
+      // isInside is based on mouseup target position
+      const isInside = element.contains(mouseupEvent.target);
+
+      const treeRoot = data.tree;
+      const currentNode = traverseTree(treeRoot, MouseRegistry.snapshotHistory);
+
+      if (!currentNode) continue;
+
+      foundAnyMatch = true;
+
+      const hasMatch = currentNode.config !== null;
+      const hasLongerSequences = currentNode.children.size > 0;
+
+      if (hasLongerSequences) {
+        anyHasLongerSequence = true;
+      }
+
+      if (hasMatch) {
+        currentMatches.push({
+          elementId: elementId,
+          config: currentNode.config,
+          combinationStr: currentNode.combinationStr,
+          isInside: isInside,
+          hasFocus: mdState.hasFocusMap[elementId] || false,
+          mousedownJsValues: mdState.mousedownJsValues[elementId] || {}
+        });
+      }
+    }
+
+    // Clear pending matches from before mousedown
+    MouseRegistry.pendingMatches = [];
+
+    // Decision logic (same pattern as handleGlobalClick)
+    if (currentMatches.length > 0 && !anyHasLongerSequence) {
+      for (const match of currentMatches) {
+        triggerMousedownUpAction(match, mouseupEvent);
+      }
+      MouseRegistry.snapshotHistory = [];
+
+    } else if (currentMatches.length > 0 && anyHasLongerSequence) {
+      MouseRegistry.pendingMatches = currentMatches.map(m => ({ ...m, mouseupEvent: mouseupEvent }));
+
+      MouseRegistry.pendingTimeout = setTimeout(() => {
+        for (const match of MouseRegistry.pendingMatches) {
+          triggerMousedownUpAction(match, match.mouseupEvent);
+        }
+        MouseRegistry.snapshotHistory = [];
+        MouseRegistry.pendingMatches = [];
+        MouseRegistry.pendingTimeout = null;
+      }, MouseRegistry.sequenceTimeout);
+
+    } else if (currentMatches.length === 0 && anyHasLongerSequence) {
+      // Wait for more input
+
+    } else {
+      MouseRegistry.snapshotHistory = [];
+    }
+
+    if (!foundAnyMatch) {
+      MouseRegistry.snapshotHistory = [];
+    }
+
+    if (MouseRegistry.snapshotHistory.length > 10) {
+      MouseRegistry.snapshotHistory = [];
+    }
+  }
+
+  /**
+   * Trigger an HTMX action for a mousedown>mouseup match.
+   * Similar to triggerHtmxAction but merges suffixed JS values from both phases.
+   * @param {Object} match - The match object with config, elementId, etc.
+   * @param {MouseEvent} mouseupEvent - The mouseup event
+   */
+  function triggerMousedownUpAction(match, mouseupEvent) {
+    const element = document.getElementById(match.elementId);
+    if (!element) return;
+
+    const config = match.config;
+
+    // Extract HTTP method and URL
+    let method = 'POST';
+    let url = null;
+
+    const methodMap = {
+      'hx-post': 'POST', 'hx-get': 'GET', 'hx-put': 'PUT',
+      'hx-delete': 'DELETE', 'hx-patch': 'PATCH'
+    };
+
+    for (const [attr, httpMethod] of Object.entries(methodMap)) {
+      if (config[attr]) {
+        method = httpMethod;
+        url = config[attr];
+        break;
+      }
+    }
+
+    if (!url) {
+      console.error('No HTTP method attribute found in config:', config);
+      return;
+    }
+
+    // Build htmx.ajax options
+    const htmxOptions = {};
+
+    if (config['hx-target']) {
+      htmxOptions.target = config['hx-target'];
+    }
+
+    if (config['hx-swap']) {
+      htmxOptions.swap = config['hx-swap'];
+    }
+
+    // Build values
+    const values = {};
+
+    // 1. Merge static hx-vals from command
+    if (config['hx-vals'] && typeof config['hx-vals'] === 'object') {
+      Object.assign(values, config['hx-vals']);
+    }
+
+    // 2. Merge mousedown JS values (already suffixed with _mousedown)
+    if (match.mousedownJsValues) {
+      Object.assign(values, match.mousedownJsValues);
+    }
+
+    // 3. Call JS function at mouseup time, suffix with _mouseup
+    if (config['hx-vals-extra']) {
+      const extra = config['hx-vals-extra'];
+
+      // Merge static dict values
+      if (extra.dict && typeof extra.dict === 'object') {
+        Object.assign(values, extra.dict);
+      }
+
+      // Call dynamic JS function and suffix with _mouseup
+      if (extra.js) {
+        try {
+          const func = window[extra.js];
+          if (typeof func === 'function') {
+            const dynamicValues = func(mouseupEvent, element, match.combinationStr);
+            if (dynamicValues && typeof dynamicValues === 'object') {
+              for (const [key, value] of Object.entries(dynamicValues)) {
+                values[key + '_mouseup'] = value;
+              }
+            }
+          }
+        } catch (e) {
+          console.error('Error calling dynamic hx-vals function at mouseup:', e);
+        }
+      }
+    }
+
+    // 4. Add auto params
+    values.combination = match.combinationStr;
+    values.has_focus = match.hasFocus;
+    values.is_inside = match.isInside;
+
+    htmxOptions.values = values;
+
+    // Add any other hx-* attributes
+    for (const [key, value] of Object.entries(config)) {
+      if (key.startsWith('hx-') && !['hx-post', 'hx-get', 'hx-put', 'hx-delete', 'hx-patch', 'hx-target', 'hx-swap', 'hx-vals', 'hx-vals-extra'].includes(key)) {
+        const optionKey = key.substring(3).replace(/-([a-z])/g, (g) => g[1].toUpperCase());
+        htmxOptions[optionKey] = value;
+      }
+    }
+
+    htmx.ajax(method, url, htmxOptions);
+  }
+
   /**
    * Attach the global mouse event listeners if not already attached
    */
@@ -497,9 +965,13 @@
       // Store handler references for proper removal
       MouseRegistry.clickHandler = (e) => handleMouseEvent(e, 'click');
       MouseRegistry.contextmenuHandler = (e) => handleMouseEvent(e, 'right_click');
+      MouseRegistry.mousedownHandler = (e) => handleMouseDown(e);
+      MouseRegistry.mouseupHandler = (e) => handleMouseUp(e);
 
       document.addEventListener('click', MouseRegistry.clickHandler);
       document.addEventListener('contextmenu', MouseRegistry.contextmenuHandler);
+      document.addEventListener('mousedown', MouseRegistry.mousedownHandler);
+      document.addEventListener('mouseup', MouseRegistry.mouseupHandler);
       MouseRegistry.listenerAttached = true;
     }
   }
@@ -511,11 +983,15 @@
     if (MouseRegistry.listenerAttached) {
       document.removeEventListener('click', MouseRegistry.clickHandler);
       document.removeEventListener('contextmenu', MouseRegistry.contextmenuHandler);
+      document.removeEventListener('mousedown', MouseRegistry.mousedownHandler);
+      document.removeEventListener('mouseup', MouseRegistry.mouseupHandler);
       MouseRegistry.listenerAttached = false;
 
       // Clean up handler references
       MouseRegistry.clickHandler = null;
       MouseRegistry.contextmenuHandler = null;
+      MouseRegistry.mousedownHandler = null;
+      MouseRegistry.mouseupHandler = null;
 
       // Clean up all state
       MouseRegistry.snapshotHistory = [];
@@ -524,6 +1000,9 @@
         MouseRegistry.pendingTimeout = null;
       }
       MouseRegistry.pendingMatches = [];
+      clearMousedownState();
+      MouseRegistry.suppressNextClick = false;
+      MouseRegistry.mousedownPending = null;
     }
   }
 

src/myfasthtml/assets/datagrid/datagrid.js

@@ -666,6 +666,32 @@ function updateDatagridSelection(datagridId) {
       document.querySelectorAll(`[data-col="${elementId}"]`).forEach((columnElement) => {
         columnElement.classList.add('dt2-selected-column');
       });
+    } else if (selectionType === 'range') {
+      // Parse range tuple string: "(min_col,min_row,max_col,max_row)"
+      // Remove parentheses and split
+      const cleanedId = elementId.replace(/[()]/g, '');
+      const parts = cleanedId.split(',');
+      if (parts.length === 4) {
+        const [minCol, minRow, maxCol, maxRow] = parts;
+
+        // Convert to integers
+        const minColNum = parseInt(minCol);
+        const maxColNum = parseInt(maxCol);
+        const minRowNum = parseInt(minRow);
+        const maxRowNum = parseInt(maxRow);
+
+        // Iterate through range and select cells by reconstructed ID
+        for (let col = minColNum; col <= maxColNum; col++) {
+          for (let row = minRowNum; row <= maxRowNum; row++) {
+            const cellId = `tcell_${datagridId}-${col}-${row}`;
+            const cell = document.getElementById(cellId);
+            if (cell) {
+              cell.classList.add('dt2-selected-cell');
+              cell.style.userSelect = 'text';
+            }
+          }
+        }
+      }
     }
   });
 }

src/myfasthtml/controls/DataGrid.py

@@ -152,6 +152,13 @@ class Commands(BaseCommands):
                    self._owner.on_click
                    ).htmx(target=f"#tsm_{self._id}")
   
+  def on_mouse_selection(self):
+    return Command("OnMouseSelection",
+                   "Range selection with mouse",
+                   self._owner,
+                   self._owner.on_mouse_selection
+                   ).htmx(target=f"#tsm_{self._id}")
+  
   def toggle_columns_manager(self):
     return Command("ToggleColumnsManager",
                    "Hide/Show Columns Manager",
@@ -231,6 +238,7 @@ class DataGrid(MultipleInstance):
     
     # other definitions
     self._mouse_support = {
+        "mousedown>mouseup": {"command": self.commands.on_mouse_selection(), "hx_vals": "js:getCellId()"},
         "click": {"command": self.commands.on_click(), "hx_vals": "js:getCellId()"},
         "ctrl+click": {"command": self.commands.on_click(), "hx_vals": "js:getCellId()"},
         "shift+click": {"command": self.commands.on_click(), "hx_vals": "js:getCellId()"},
@@ -479,12 +487,30 @@ class DataGrid(MultipleInstance):
   def on_click(self, combination, is_inside, cell_id):
     logger.debug(f"on_click {combination=} {is_inside=} {cell_id=}")
     if is_inside and cell_id:
+      self._state.selection.extra_selected.clear()
+      
       if cell_id.startswith("tcell_"):
         pos = self._get_pos_from_element_id(cell_id)
         self._update_current_position(pos)
     
     return self.render_partial()
   
+  def on_mouse_selection(self, combination, is_inside, cell_id_mousedown, cell_id_mouseup):
+    logger.debug(f"on_mouse_selection {combination=} {is_inside=} {cell_id_mousedown=} {cell_id_mouseup=}")
+    if (is_inside and
+        cell_id_mousedown and cell_id_mouseup and
+        cell_id_mousedown.startswith("tcell_") and cell_id_mouseup.startswith("tcell_")):
+      pos_mouse_down = self._get_pos_from_element_id(cell_id_mousedown)
+      pos_mouse_up = self._get_pos_from_element_id(cell_id_mouseup)
+      
+      min_col, max_col = min(pos_mouse_down[0], pos_mouse_up[0]), max(pos_mouse_down[0], pos_mouse_up[0])
+      min_row, max_row = min(pos_mouse_down[1], pos_mouse_up[1]), max(pos_mouse_down[1], pos_mouse_up[1])
+      
+      self._state.selection.extra_selected.clear()
+      self._state.selection.extra_selected.append(("range", (min_col, min_row, max_col, max_row)))
+    
+    return self.render_partial()
+  
   def on_column_changed(self):
     logger.debug("on_column_changed")
     return self.render_partial("table")
@@ -752,6 +778,9 @@ class DataGrid(MultipleInstance):
       # selected.append(("cell", self._get_element_id_from_pos("cell", self._state.selection.selected)))
       selected.append(("focus", self._get_element_id_from_pos("cell", self._state.selection.selected)))
     
+    for extra_sel in self._state.selection.extra_selected:
+      selected.append(extra_sel)
+    
     return Div(
       *[Div(selection_type=s_type, element_id=f"{elt_id}") for s_type, elt_id in selected],
       id=f"tsm_{self._id}",

src/myfasthtml/controls/Mouse.py

@@ -19,11 +19,62 @@ class Mouse(MultipleInstance):
   - Both (named params override command): mouse.add("click", command, hx_target="#other")
 
   For dynamic hx_vals, use "js:functionName()" to call a client-side function.
+
+  Supported base actions:
+  - ``click`` - Left mouse click (detected globally)
+  - ``right_click`` (or alias ``rclick``) - Right mouse click (detected on element only)
+  - ``mousedown>mouseup`` - Left mouse press-and-release (captures data at both phases)
+  - ``rmousedown>mouseup`` - Right mouse press-and-release
+
+  Modifiers can be combined with ``+``: ``ctrl+click``, ``shift+mousedown>mouseup``.
+  Sequences use space separation: ``click right_click``, ``click mousedown>mouseup``.
+
+  For ``mousedown>mouseup`` actions with ``hx_vals="js:functionName()"``, the JS function
+  is called at both mousedown and mouseup. Results are suffixed: ``key_mousedown`` and
+  ``key_mouseup`` in the server request.
   """
+
+  VALID_ACTIONS = {
+    'click', 'right_click', 'rclick',
+    'mousedown>mouseup', 'rmousedown>mouseup'
+  }
+  VALID_MODIFIERS = {'ctrl', 'shift', 'alt'}
   def __init__(self, parent, _id=None, combinations=None):
     super().__init__(parent, _id=_id)
     self.combinations = combinations or {}
 
+  def _validate_sequence(self, sequence: str):
+    """
+    Validate a mouse event sequence string.
+
+    Checks that all elements in the sequence use valid action names and modifiers.
+
+    Args:
+        sequence: Mouse event sequence string (e.g., "click", "ctrl+mousedown>mouseup")
+
+    Raises:
+        ValueError: If any action or modifier is invalid.
+    """
+    elements = sequence.strip().split()
+    for element in elements:
+      parts = element.split('+')
+      # Last part should be the action, others are modifiers
+      action = parts[-1].lower()
+      modifiers = [p.lower() for p in parts[:-1]]
+
+      if action not in self.VALID_ACTIONS:
+        raise ValueError(
+          f"Invalid action '{action}' in sequence '{sequence}'. "
+          f"Valid actions: {', '.join(sorted(self.VALID_ACTIONS))}"
+        )
+
+      for mod in modifiers:
+        if mod not in self.VALID_MODIFIERS:
+          raise ValueError(
+            f"Invalid modifier '{mod}' in sequence '{sequence}'. "
+            f"Valid modifiers: {', '.join(sorted(self.VALID_MODIFIERS))}"
+          )
+
   def add(self, sequence: str, command: Command = None, *,
           hx_post: str = None, hx_get: str = None, hx_put: str = None,
           hx_delete: str = None, hx_patch: str = None,
@@ -32,7 +83,11 @@ class Mouse(MultipleInstance):
     Add a mouse combination with optional command and HTMX parameters.
 
     Args:
-        sequence: Mouse event sequence (e.g., "click", "ctrl+click", "click right_click")
+        sequence: Mouse event sequence string. Supports:
+            - Simple actions: ``"click"``, ``"right_click"``, ``"mousedown>mouseup"``
+            - Modifiers: ``"ctrl+click"``, ``"shift+mousedown>mouseup"``
+            - Sequences: ``"click right_click"``, ``"click mousedown>mouseup"``
+            - Aliases: ``"rclick"`` for ``"right_click"``
         command: Optional Command object for server-side action
         hx_post: HTMX post URL (overrides command)
         hx_get: HTMX get URL (overrides command)
@@ -41,11 +96,17 @@ class Mouse(MultipleInstance):
         hx_patch: HTMX patch URL (overrides command)
         hx_target: HTMX target selector (overrides command)
         hx_swap: HTMX swap strategy (overrides command)
-        hx_vals: HTMX values dict or "js:functionName()" for dynamic values
+        hx_vals: HTMX values dict or "js:functionName()" for dynamic values.
+            For mousedown>mouseup actions, the JS function is called at both
+            mousedown and mouseup, with results suffixed ``_mousedown`` and ``_mouseup``.
 
     Returns:
         self for method chaining
+
+    Raises:
+        ValueError: If the sequence contains invalid actions or modifiers.
     """
+    self._validate_sequence(sequence)
     self.combinations[sequence] = {
       "command": command,
       "hx_post": hx_post,

src/myfasthtml/controls/datagrid_objects.py

@@ -30,10 +30,15 @@ class DatagridEditionState:
 
 @dataclass
 class DatagridSelectionState:
+  """
+  element_id: str
+    "tcell_grid_id_col_row" for cell
+    (min_col, min_row, max_col, max_row) for range
+  """
   selected: tuple[int, int] | None = None  # column first, then row
   last_selected: tuple[int, int] | None = None
-  selection_mode: str = None  # valid values are "row", "column" or None for "cell"
+  selection_mode: str = None  # valid values are "row", "column", "range" or None for "cell"
-  extra_selected: list[tuple[str, str | int]] = field(default_factory=list)  # list(tuple(selection_mode, element_id))
+  extra_selected: list[tuple[str, str | int | tuple]] = field(default_factory=list)  # (selection_mode, element_id)
   last_extra_selected: tuple[int, int] = None
 
 

src/myfasthtml/core/commands.py

@@ -125,8 +125,6 @@ class Command:
   
   def execute(self, client_response: dict = None):
     logger.debug(f"Executing command {self.name} with arguments {client_response=}")
-    if self._htmx_extra.get("hx-target", "").startswith("#tsm_"):
-      logger.warning(f"  Command {self.name} needs a selection manager to work properly.")
     with ObservableResultCollector(self._bindings) as collector:
       kwargs = self._create_kwargs(self.default_kwargs,
                                    client_response,
@@ -150,10 +148,6 @@ class Command:
             and r.get("id", None) is not None):
           r.attrs["hx-swap-oob"] = r.attrs.get("hx-swap-oob", "true")
     
-    if self._htmx_extra.get("hx-target", "").startswith("#tsm_"):
-      ret_debug = [f"<{r.tag} id={r.attrs.get('id', '')}/>" if r else "None" for r in all_ret]
-      logger.warning(f"  {ret_debug=}")
-    
     return all_ret[0] if len(all_ret) == 1 else all_ret
   
   def htmx(self, target: Optional[str] = "this", swap="outerHTML", trigger=None, auto_swap_oob=True):

tests/html/test_mouse_support.html

@@ -159,6 +159,14 @@
       <li><code>rclick</code> - Right click (using rclick alias)</li>
       <li><code>click rclick</code> - Click then right-click sequence (using alias)</li>
     </ul>
+    <p><strong>Element 3 - Mousedown&gt;mouseup actions:</strong></p>
+    <ul>
+      <li><code>click</code> - Simple click (coexists with mousedown&gt;mouseup)</li>
+      <li><code>mousedown>mouseup</code> - Left press and release (with JS values)</li>
+      <li><code>ctrl+mousedown>mouseup</code> - Ctrl + press and release</li>
+      <li><code>rmousedown>mouseup</code> - Right press and release</li>
+      <li><code>click mousedown>mouseup</code> - Click then press-and-release sequence</li>
+    </ul>
     <p><strong>Note:</strong> <code>rclick</code> is an alias for <code>right_click</code> and works identically.</p>
     <p><strong>Tip:</strong> Try different click combinations! Right-click menu will be blocked on test elements.</p>
   </div>
@@ -197,6 +205,14 @@
     </button>
   </div>
 
+  <div class="test-container">
+    <h2>Test Element 3 (Mousedown&gt;mouseup actions)</h2>
+    <div id="test-element-3" class="test-element" tabindex="0">
+      Try mousedown&gt;mouseup actions here!<br>
+      Press and hold, then release. Also try Ctrl+drag, right-drag, and click then drag.
+    </div>
+  </div>
+
   <div class="test-container">
     <h2>Test Input (normal clicking should work here)</h2>
     <input type="text" placeholder="Try clicking, right-clicking here - should work normally"
@@ -346,10 +362,48 @@
 
     add_mouse_support('test-element-2', JSON.stringify(combinations2));
 
+    // JS function for dynamic mousedown>mouseup values
+    // Returns cell-like data for testing
+    window.getCellId = function(event, element, combination) {
+      const x = event.clientX;
+      const y = event.clientY;
+      return {
+        cell_id: `cell-${Math.floor(x / 50)}-${Math.floor(y / 50)}`,
+        x: x,
+        y: y
+      };
+    };
+
+    // Element 3 - Mousedown>mouseup actions
+    const combinations3 = {
+      "click": {
+        "hx-post": "/test/element3-click"
+      },
+      "mousedown>mouseup": {
+        "hx-post": "/test/element3-mousedown-mouseup",
+        "hx-vals-extra": {"js": "getCellId"}
+      },
+      "ctrl+mousedown>mouseup": {
+        "hx-post": "/test/element3-ctrl-mousedown-mouseup",
+        "hx-vals-extra": {"js": "getCellId"}
+      },
+      "rmousedown>mouseup": {
+        "hx-post": "/test/element3-rmousedown-mouseup",
+        "hx-vals-extra": {"js": "getCellId"}
+      },
+      "click mousedown>mouseup": {
+        "hx-post": "/test/element3-click-then-mousedown-mouseup",
+        "hx-vals-extra": {"js": "getCellId"}
+      }
+    };
+
+    add_mouse_support('test-element-3', JSON.stringify(combinations3));
+
     // Log initial state
     logEvent('Mouse support initialized',
              'Element 1: All mouse actions configured',
              'Element 2: Using "rclick" alias (click, rclick, and click rclick sequence)',
+             'Element 3: Mousedown>mouseup actions (with JS getCellId function)',
              'Smart timeout: 500ms for sequences', false);
   </script>
 </body>