This problem started after upgrade from Ubuntu 22.10 to 23.04.
For example, open gnome-terminal (Terminal) and usb-creator-gtk (Startup Disk Creator). Partially overlap these two windows and allow the title bars of both windows to be visible (and clickable).
Click on the title bar of Terminal; it will be focused. Now, click on the title bar (the topmost area saying "Make Startup Disk") of Startup Disk Creator; it will not be focused and Terminal will remain focused.
The only seemingly workaround is to click and drag a bit the title bar of Startup Disk Creator or click somewhere inside the window of Startup Disk Creator.
The same problem is present in LibreOffice applications, Thunderbird and Firefox with title bar enabled.
This is a rather annoying bug not present in the previous versions of Ubuntu.
Note that this problem is not present on all Ubuntu applications and it may be related to the version of GTK used in that application.
How to correct this wrong behavior?
