When using a stylus pen, after undocking a QDockWidget, it cannot be re-docked by dragging the floating window back into a dock area.

• This issue occurs only with stylus input.

• In Qt 5.15, docking with a stylus works correctly.

• If the widget is dragged into the dock area as part of the same drag operation that caused the undocking, docking still works. The problem occurs only when trying to re-dock after the widget has already been undocked.

Expected behavior:
A QDockWidget should be dockable into a dock area even when dragged with a stylus pen after it has been undocked.

Steps to reproduce:

1. Extract and build the attached dock_test.zip.
2. Run the application.
3. Use a stylus pen to drag the dock widget and undock it.
4. Try to drag the undocked dock widget with the stylus pen back into the dock area.
5. Observe that the widget does not dock.