diff --git a/src/myfasthtml/controls/DataGrid.py b/src/myfasthtml/controls/DataGrid.py
index 53aba86..478ab04 100644
--- a/src/myfasthtml/controls/DataGrid.py
+++ b/src/myfasthtml/controls/DataGrid.py
@@ -57,7 +57,7 @@ class DataGrid(MultipleInstance):
   
   def render(self):
     return Div(
-      NotStr(self._state.html),
+      NotStr(self._state.html) if self._state.html else "Content lost !",
       id=self._id
     )
   
diff --git a/src/myfasthtml/controls/DataGridsManager.py b/src/myfasthtml/controls/DataGridsManager.py
index bdb9ef1..29ce8c5 100644
--- a/src/myfasthtml/controls/DataGridsManager.py
+++ b/src/myfasthtml/controls/DataGridsManager.py
@@ -1,3 +1,4 @@
+import uuid
 from dataclasses import dataclass
 
 import pandas as pd
@@ -10,7 +11,7 @@ from myfasthtml.controls.Panel import Panel
 from myfasthtml.controls.TabsManager import TabsManager
 from myfasthtml.controls.TreeView import TreeView, TreeNode
 from myfasthtml.controls.helpers import mk
-from myfasthtml.core.commands import Command, LambdaCommand
+from myfasthtml.core.commands import Command
 from myfasthtml.core.dbmanager import DbObject
 from myfasthtml.core.instances import MultipleInstance, InstancesManager
 from myfasthtml.icons.fluent_p1 import table_add20_regular
@@ -19,6 +20,7 @@ from myfasthtml.icons.fluent_p3 import folder_open20_regular
 
 @dataclass
 class DocumentDefinition:
+  document_id: str
   namespace: str
   name: str
   type: str
@@ -30,7 +32,7 @@ class DataGridsState(DbObject):
   def __init__(self, owner, name=None):
     super().__init__(owner, name=name)
     with self.initializing():
-      self.elements: list = []
+      self.elements: list = [DocumentDefinition]
 
 
 class Commands(BaseCommands):
@@ -61,7 +63,11 @@ class Commands(BaseCommands):
                    self._owner.clear_tree).htmx(target=f"#{self._owner._tree.get_id()}")
   
   def show_document(self):
-    return LambdaCommand(self._owner, lambda: print("show_document"))
+    return Command("ShowDocument",
+                   "Show document",
+                   self._owner,
+                   self._owner.select_document,
+                   key="SelectNode")
 
 
 class DataGridsManager(MultipleInstance):
@@ -89,18 +95,29 @@ class DataGridsManager(MultipleInstance):
     dg = DataGrid(self._tabs_manager)
     dg.set_html(html)
     document = DocumentDefinition(
+      document_id=str(uuid.uuid4()),
       namespace=file_upload.get_file_basename(),
       name=file_upload.get_sheet_name(),
       type="excel",
       tab_id=tab_id,
       datagrid_id=dg.get_id()
     )
-    self._state.elements = self._state.elements + [document]
+    self._state.elements = self._state.elements + [document]  # do not use append() other it won't be saved
     parent_id = self._tree.ensure_path(document.namespace)
     tree_node = TreeNode(label=document.name, type="excel", parent=parent_id)
     self._tree.add_node(tree_node, parent_id=parent_id)
     return self._mk_tree(), self._tabs_manager.change_tab_content(tab_id, document.name, Panel(self).set_main(dg))
   
+  def select_document(self, node_id):
+    document_id = self._tree.get_bag(node_id)
+    try:
+      document = next(filter(lambda x: x.document_id == document_id, self._state.elements))
+      dg = DataGrid(self._tabs_manager, _id=document.datagrid_id)
+      return self._tabs_manager.show_or_create_tab(document.tab_id, document.name, dg)
+    except StopIteration:
+      # the selected node is not a document (it's a folder)
+      return None
+  
   def clear_tree(self):
     self._state.elements = []
     self._tree.clear()
@@ -117,7 +134,11 @@ class DataGridsManager(MultipleInstance):
     tree = TreeView(self, _id="-treeview")
     for element in self._state.elements:
       parent_id = tree.ensure_path(element.namespace)
-      tree.add_node(TreeNode(label=element.name, type=element.type, parent=parent_id, id=element.datagrid_id))
+      tree.add_node(TreeNode(id=element.document_id,
+                             label=element.name,
+                             type=element.type,
+                             parent=parent_id,
+                             bag=element.document_id))
     return tree
   
   def render(self):
diff --git a/src/myfasthtml/controls/Panel.py b/src/myfasthtml/controls/Panel.py
index d7242b6..d27e46d 100644
--- a/src/myfasthtml/controls/Panel.py
+++ b/src/myfasthtml/controls/Panel.py
@@ -40,7 +40,7 @@ class PanelIds:
 
 @dataclass
 class PanelConf:
-  left: bool = True
+  left: bool = False
   right: bool = True
 
 
diff --git a/src/myfasthtml/controls/TabsManager.py b/src/myfasthtml/controls/TabsManager.py
index 9935fff..2eb82a9 100644
--- a/src/myfasthtml/controls/TabsManager.py
+++ b/src/myfasthtml/controls/TabsManager.py
@@ -58,29 +58,34 @@ class TabsManagerState(DbObject):
 
 class Commands(BaseCommands):
   def show_tab(self, tab_id):
-    return Command(f"{self._prefix}ShowTab",
+    return Command(f"ShowTab",
                    "Activate or show a specific tab",
                    self._owner,
                    self._owner.show_tab,
                    args=[tab_id,
                          True,
-                         False]).htmx(target=f"#{self._id}-controller", swap="outerHTML")
+                         False],
+                   key=f"{self._owner.get_full_id()}-ShowTab-{tab_id}",
+                   ).htmx(target=f"#{self._id}-controller", swap="outerHTML")
   
   def close_tab(self, tab_id):
-    return Command(f"{self._prefix}CloseTab",
+    return Command(f"CloseTab",
                    "Close a specific tab",
                    self._owner,
                    self._owner.close_tab,
-                   args=[tab_id]).htmx(target=f"#{self._id}-controller", swap="outerHTML")
+                   kwargs={"tab_id": tab_id},
+                   ).htmx(target=f"#{self._id}-controller", swap="outerHTML")
   
   def add_tab(self, label: str, component: Any, auto_increment=False):
-    return Command(f"{self._prefix}AddTab",
+    return Command(f"AddTab",
                    "Add a new tab",
                    self._owner,
                    self._owner.on_new_tab,
                    args=[label,
                          component,
-                         auto_increment]).htmx(target=f"#{self._id}-controller", swap="outerHTML")
+                         auto_increment],
+                   key="#{id-name-args}",
+                   ).htmx(target=f"#{self._id}-controller", swap="outerHTML")
 
 
 class TabsManager(MultipleInstance):
@@ -148,6 +153,13 @@ class TabsManager(MultipleInstance):
     tab_id = self.create_tab(label, component)
     return self.show_tab(tab_id, oob=False)
   
+  def show_or_create_tab(self, tab_id, label, component, activate=True):
+    logger.debug(f"show_or_create_tab {tab_id=}, {label=}, {component=}, {activate=}")
+    if tab_id not in self._state.tabs:
+      self._add_or_update_tab(tab_id, label, component, activate)
+    
+    return self.show_tab(tab_id, activate=activate, oob=True)
+  
   def create_tab(self, label: str, component: Any, activate: bool = True) -> str:
     """
     Add a new tab or update an existing one with the same component type, ID and label.
diff --git a/src/myfasthtml/controls/TreeView.py b/src/myfasthtml/controls/TreeView.py
index b5dfea3..0a7aeda 100644
--- a/src/myfasthtml/controls/TreeView.py
+++ b/src/myfasthtml/controls/TreeView.py
@@ -267,6 +267,12 @@ class TreeView(MultipleInstance):
     self._state.update(state)
     return self
   
+  def get_bag(self, node_id: str):
+    try:
+      return self._state.items[node_id].bag
+    except KeyError:
+      return None
+  
   def _toggle_node(self, node_id: str):
     """Toggle expand/collapse state of a node."""
     if node_id in self._state.opened:
diff --git a/src/myfasthtml/core/commands.py b/src/myfasthtml/core/commands.py
index c24eab5..ff07149 100644
--- a/src/myfasthtml/core/commands.py
+++ b/src/myfasthtml/core/commands.py
@@ -1,5 +1,6 @@
 import inspect
 import json
+import logging
 import uuid
 from typing import Optional
 
@@ -8,6 +9,8 @@ from myutils.observable import NotObservableError, ObservableResultCollector
 from myfasthtml.core.constants import Routes, ROUTE_ROOT
 from myfasthtml.core.utils import flatten
 
+logger = logging.getLogger("Commands")
+
 
 class Command:
   """
@@ -26,6 +29,33 @@ class Command:
   :type description: str
   """
   
+  @staticmethod
+  def process_key(key, name, owner, args, kwargs):
+    def _compute_from_args():
+      res = []
+      for arg in args:
+        if hasattr(arg, "get_full_id"):
+          res.append(arg.get_full_id())
+        else:
+          res.append(str(arg))
+      return "-".join(res)
+    
+    # special management when kwargs are provided
+    # In this situation,
+    #   either there is no parameter (so one single instance of the command is enough)
+    #   or the parameter is a kwargs (so the parameters are provided when the command is called)
+    if (key is None
+        and owner is not None
+        and args is None  # args is not provided
+    ):
+      key = f"{owner.get_full_id()}-{name}"
+    
+    key = key.replace("#{args}", _compute_from_args())
+    key = key.replace("#{id}", owner.get_full_id())
+    key = key.replace("#{id-name-args}", f"{owner.get_full_id()}-{name}-{_compute_from_args()}")
+    
+    return key
+  
   def __init__(self, name,
                description,
                owner=None,
@@ -47,10 +77,20 @@ class Command:
     self._callback_parameters = dict(inspect.signature(callback).parameters) if callback else {}
     self._key = key
     
+    # special management when kwargs are provided
+    # In this situation,
+    #   either there is no parameter (so one single instance of the command is enough)
+    #   or the parameter is a kwargs (so the parameters are provided when the command is called)
+    if (self._key is None
+        and self.owner is not None
+        and args is None  # args is not provided
+    ):
+      self._key = f"{owner.get_full_id()}-{name}"
+    
     # register the command
     if auto_register:
-      if key in CommandsManager.commands_by_key:
-        self.id = CommandsManager.commands_by_key[key].id
+      if self._key in CommandsManager.commands_by_key:
+        self.id = CommandsManager.commands_by_key[self._key].id
       else:
         CommandsManager.register(self)
   
@@ -78,6 +118,7 @@ class Command:
     return res
   
   def execute(self, client_response: dict = None):
+    logger.debug(f"Executing command {self.name}")
     with ObservableResultCollector(self._bindings) as collector:
       kwargs = self._create_kwargs(self.default_kwargs,
                                    client_response,
@@ -87,6 +128,7 @@ class Command:
       ret_from_bound_commands = []
       if self.owner:
         for command in self.owner.get_bound_commands(self.name):
+          logger.debug(f"  will execute bound command {command.name}...")
           r = command.execute(client_response)
           ret_from_bound_commands.append(r)  # it will be flatten if needed later
     
diff --git a/src/myfasthtml/core/utils.py b/src/myfasthtml/core/utils.py
index addfea4..64bb40c 100644
--- a/src/myfasthtml/core/utils.py
+++ b/src/myfasthtml/core/utils.py
@@ -12,7 +12,7 @@ from myfasthtml.core.constants import Routes, ROUTE_ROOT
 from myfasthtml.test.MyFT import MyFT
 
 utils_app, utils_rt = fast_app()
-logger = logging.getLogger("Commands")
+logger = logging.getLogger("Routing")
 
 
 def mount_if_not_exists(app, path: str, sub_app):
diff --git a/tests/controls/test_panel.py b/tests/controls/test_panel.py
index 4c95872..44b29ce 100644
--- a/tests/controls/test_panel.py
+++ b/tests/controls/test_panel.py
@@ -24,7 +24,7 @@ class TestPanelBehaviour:
     panel = Panel(root_instance)
 
     assert panel is not None
-    assert panel.conf.left is True
+    assert panel.conf.left is False
     assert panel.conf.right is True
 
   def test_i_can_create_panel_with_custom_config(self, root_instance):
@@ -157,7 +157,7 @@ class TestPanelBehaviour:
     """Test that update_side_width() returns a panel element."""
     panel = Panel(root_instance)
 
-    result = panel.update_side_width("left", 300)
+    result = panel.update_side_width("right", 300)
 
     assert result is not None
 
@@ -196,7 +196,7 @@ class TestPanelRender:
 
   @pytest.fixture
   def panel(self, root_instance):
-    panel = Panel(root_instance)
+    panel = Panel(root_instance, PanelConf(True, True))
     panel.set_main(Div("Main content"))
     panel.set_left(Div("Left content"))
     panel.set_right(Div("Right content"))