Need to tap F12 three times to make it focus on guake terminal

I'm on ubuntu16 unity. Recently I found that the system does not focus on guake when I tap F12, although guake jumps up. Instead, it focuses on the last window, like chrome or some other apps.

And I need to tap F12 again to close it and tap F12 thrice to reopen it, and now, the guake focuses on guake. I think maybe guake thinks that it needs to focus on the last app.

It's a little annoy, can you tell me how to fix it?

Thank you,
Neo