Hotkey functions lost

Odd observation.
I use both Cantabile (lastest version) and Studio One 4 DAW.
I keep them both open in Windows 7 on a laptop I use for daily music work with Cantabile and my notation software.
When a song finishes in Studio One, and I toggle to the other Cantabile window (using the alt-tab keystroke), I find that I have lost all shortcut key functions. (like the space bar will not start the Cantabile song). BUT, if I use the cursor to click on the media player start arrow at the top, it works.
I have to close Cantabile and reopen it to regain the shortcut key functions. Happens every time I toggle back to Cantabile from Studio One after playing a song on Studio One.
This Does not happen on my Windows 10 laptop which I use for performances. .
Anyone know how I can repair this?

I just discovered, this also doesn’t happen if I minimize the studio one window after the song, using the - button, and maximize the cantabile window using the + button. The problem appears to be related to the windows toggle feature.