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All the controls are firing their loaded events when they appear in the visual tree. If there is only one pane in a RadPaneGroup it hides its tab strip area (where the panes are displayed) and the pane never gets shown. On the other hand its content gets added to the visual tree and its loaded event is fired. If you have more than one pane in a pane group, the loaded event only of the selected pane will be fired, because the content of all other panes is actually not visible (a similar thing happens when you use tab control). When the user selects another pane, its content gets added to the visual tree and the content of the previous one is removed from it.
The content of the pane is not part of its visual tree - it is actually part of the visual tree of the pane group. On the other hand the pane group displays only the selected pane and if there are more than one the others are actually not in the visual tree at all.
When a Pane is made floating it is taken out of the Visual Tree, new pane group is created and put in the ToolWindow.
When the state of the Pane is changed it is taken out from this visual tree and put into another one.
This is how the RadDocking is working.
Hope this information helps. If you have any other questions please let us know.
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