well at least you have a work around, but Kodi shouldn't be different on a mac.
some pics to help, use arrow keys and enter to avoid clicking the wrong tabs
Highlight "System" in the main toolbar and press enter
this will bring you to a screen with "Appearence" as the first option, use your arrow keys to scroll down to "System" and press "enter"
The first option is Video output, highlight "Display Mode"
Click the little arrow once and it will change the view to windowed
Ta DAAAAAA
done
oooops i'm tyurning ad block off now ric XxxX