Windows Popping Up Behind Main Window

I was hoping someone else has experienced this and found a solution.

It seems to happen randomly.  The pop-up box for general Primavera messages and warnings (eg. activity deletion warning, resource deletion warning) will sometimes appear behind the main screen.  When this happens, it appears that the software is frozen because you can't see it, and it's waiting for a response to close it.  The workaround is to Ctrl-Alt-Del, Task Manager, then close the Task Manager. This will bring the pop-up to the front of the screen, where the user can then click OK to close it.

Anyone experience this? It's been an ongoing issue for quite some time.