My system is Ubuntu 20.04. I'm trying to learn how to use Scribus. I realized that some property windows make the main document grayed out. That's all good, but when I try to move the floating property window, the whole windows with the grayed out main document move altogether and even change the size. Is it normal behavior of windows in ubuntu 20.04? I remember other programs like gimp do so as well in Ubuntu 20.04.
SnapOverflow
This may be an undesired effect of the "Attach Modal Dialogs" feature. With this setting on, a modal dialog is attached to the parent window, and cannot be moved. This is on by default in Gnome Shell.
Turn this feature off in Gnome Tweaks, on the "Windows" tab. Then, these dialogs will behave independently as any other windows. It then becomes possible to move it to see what is underneath if needed.