I usually have a problem with the print preview window not displaying. When that happens I use Alt+Tab and then holding down the Alt key press the Tab key to move through the windows that are open ending with P6 Professional. I then see the print preview window. Maybe this would work for the Find dialog box too?
That works for me sometimes when I have issues with the print window, I press the Alt+Tab twice and it shows. but i wasn't able to do the same with the ind window. remember I'm connecting to a remote server where the P6 Application is installed, I think it is showing on the server other screen but then my local Alt+tab combination won't work