QMainWindow does not update cursor when floating dock widget is undocked.

When Dockwidget is dragged and then mouse hovered over main window cursor is not updated and still show arrow instead of I-beam.

This can be seen with Qt example of dock wideget.

Drag to undock one of the dock widgets.
Move your mouse over the main window.
Notice you get the arrow cursor and not the I-beam.
Click on the main window.
Now you get the I-beam.
Click on the floating dock widget.
Mouse over the main window again.
Notice you get the arrow cursor again.

This worked correctly in Qt 5.9.7