The LayoutChange events are fired for continuous operations like dragging a pane, resizing a pane or moving a ToolWindow. It is not guaranteed that it fires when a state of a pane is changed. In this case you might use the PaneStateChanged or Pinned/Unpinned events.
Hope this helps.
All the best,
the Telerik team
Sharpen your .NET Ninja skills
! Attend Q1 webinar week and get a chance to win a license! Book your seat now >>