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    Bug 
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    Resolution: Unresolved
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    P2: Important 
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    None
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    5.6.3, 5.12.1
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    None
After setting a custom title widget (setTitleBarWidget) on a QDockWidget, it is not resizable while it is floating/undocked.
Reproducible with the "blue" dock widget in the standard main window example.
This seems to be a regression in Qt 5.6.3 and later, since supposedly this worked in Qt 5.5 (QTBUG-47977) and I was able to reproduce with 5.6.3, 5.9.x and 5.12.0+.1.
This affects the debugger dock widgets in Qt Creator.