Menu bar goes black w/ Mission Control

So I'm not very technically inclined when it comes to computers, so forgive me.

I've had this problem for a while where when I activate my mission control hot corner with my mouse and select a different desktop, there's about a 50/50 chance that the menu bar on the desktop I'm going to will be blacked out. I can go back and forth between several desktops with similar results. The problem also occurs when I use the mission control key on the keyboard (F3).

One weird thing: if my menu bar is blacked out and I activate mission control, and then instead of selecting a desktop I just deactivate mission control, the menu bar is restored every time. It only goes black when I select a different desktop. This is really annoying though because it makes my computing experience feel erratic and crazy as I engage and disengage mission control unnecessarily.

I found this old thread post where someone seemed to have a similar issue, but it didn't help me. Hopefully someone on here has some idea as to what's up.

I'm using a late-2009 imac w/ 10.10.

Thanks!