This is described in the manual and depends on the used operating system.
Especially on Linux it also depends on the used window manager, this is nothing we can fix in LibreCAD.
https://docs.librecad.org/en/2.2.0_a/ref/menu.html#main-menuUsually the dashed line appear in the docked menu and clicking it undocks the menu. This is how it works for me on KDE Linux and Windows. The floating menu then has a close button in the title bar to re-dock it. Also the undocked menus don't disappear from the menu bar, they are still accessible, even when the floating menu is there.
Maybe this happens by accident, e.g. by moving the mouse during clicking? Or do you have a different pointing device which can cause this?
Anyhow, the suggestion from @dellus should solve it without reinstalling.
Maybe the Fedora community has an advice for this behavior.
Armin
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