[Bug 56911] System.Windows.Forms: ContextMenuStrip -> SourceControl property is null

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56911

--- Comment #8 from Esme Povirk  ---
This is unset by the SetOwnerControl(null) call in ToolStripDropDown.Close.
Unfortunately, moving the call to the end doesn't fix this, and I found in
testing on Wine (which probably matches Windows) that it is unset later. So I'm
not sure where the unset call should be.