Move window overlay up to be a sibling of the frame

Bug: 71178
Change-Id: I7e0294bb1dfc3c0fe32ad1070926f1e24e55d6e5
ComboBoxWidget: Append menu to $overlay option

Bug: 71178
Change-Id: I0a39ae702e3fccf5bfb6d27299bd640ac2fa5c94
Merge "Move window overlay up to be a sibling of the frame"
Merge "ComboBoxWidget: Append menu to $overlay option"