Abnormal window size behavior
For no reason I can name, Firefox's window sizing has gone bonkers.
I'm using Firefox 101.0.1 with Microsoft Windows 10 Enterprise. I have two Firefox windows open.
When I unlock the computer after a period of non-use, the Firefox task bar icon has two white bars at the edge, indicating that two windows are open, but the windows not visible. Quitting and restarting Firefox does not help.
To recover the first window I must float the mouse over the task bar icon, opening thumbnails of the windows, then right click the first thumbnail and select Maximize. This makes the maximized window appear. Then I can drag the window away from the edge of the screen, reducing its size. After that it behaves normally until the computer is locked and unlocked; then the process repeats.
I can't recover the second window at all. Its thumbnail is empty except for a tiny rectangle in the upper left corner, presumably representing a tiny window. When I right click the thumbnail it doesn't open a menu; it just displays a blue rectangle as high as a normal window's title bar and about four times wider than high. Presumably this is what's left of the window. It has no title, no minimize/maximize/close buttons, and no system menu icon. Trying to change its size by dragging its edges has no effect. Nor does trying to maximize it by pushing it up to the top edge of the desktop.
What can I do to make Firefox behave normally? How can I prevent this from happening again?