Welcome to the community.
Have you recently gone from a dual monitor setup to a single monitor? When this happens, RH can sometimes keep tossing dialog boxes over where it thinks the second monitor is. I typically use a program called ForceWindowVisible (get it here) to push wandering dialogs back into view. Give that a try and see if it works. Hope this helps,
A lot of windows also allow you to"snag" the window with the following keys:
Perform your action so that the window should be in focus, e.g. Insert > Image.
Press Alt, Spacebar, M.
Press any arrow key.
Waggle the mouse around wildly until the cursor and attached window display on your screen.
Left-click to drop the window.
We were having the same problems, and we had a good laugh when we read Amebr's suggestion, which seemed pretty crazy. But it worked! It solved several different problems we were having with both RH and other programs. Thank you!
thanks so much...I just can't believe my eyes...after a long long time, my windows are visible again.