Could you please clarify what exactly you are trying to achieve? If you want to display a list of all open panes you can do that by using the Docking's Panes collection which gets the list of all panes. Then check if there is a newly opened Pane via Docking's Show event and if yes add it to your list.
Attached you will find a sample project in which that is illustrated.
If you have further questions please feel free to contact us again.
Greetings,
Konstantina
the Telerik team
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