Docking Pane - Exception occurs trying to collapse pane

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Exception occurs trying to collapse pane

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Category: Codejock Products
Forum Name: Docking Pane
Forum Description: Topics Related to Codejock Docking Pane
URL: https://forum.codejock.com/forum_posts.asp?TID=3323
Printed Date: 15 November 2026 at 7:44am
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Topic: Exception occurs trying to collapse pane

Posted By: thawary
Subject: Exception occurs trying to collapse pane
Date Posted: 01 December 2005 at 9:03am

The following are steps required to create the problem:

1) Dock a pane
2) Press the pin on the top of the pane to autohide it
3) Press on the pane to show it (Expand the pane)
3) do something that takes time in the application while the pane is not hidden (not collapsed)
4) Wait for a second and try to collapse the pane by pressing on the pin while the lengthy operation is taking place
5) The following exception occurs:

"System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageA(MS G& msg)
   at System.Windows.Forms.ComponentManager.System.Windows.Forms.U nsafeNativeMethods+IMsoComponentManager.FPushMessageLoop(Int 32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)"

and i think it happens because the lengthy operation freezes the screen while the docking manager internally or something collapses the pane, but it is still expanded in front of the user so when he presses the pin again the null reference exception happens in your docking manager