Hi @johnnyangel
I’m on Mac also. If we don’t have show/hide, you may (inadvertently) hide the filmstrip by dragging the upper border at the bottom of the screen.
Then it disappear, and doing Cmd+U make it appear separately and disappear again by Cmd+U.
You can put your cursor over the button of PhotoLab window until you see it changing to an icon with a bar and upper arrow which allow to drag it upper, and then once the space available is enough you should recover the filmstrip.
As I’m on Mac Intel this may not solve your issue and perhaps you already know this, otherwise it may be worth a try.