Fix flickering scrollbar in projectors

current behaviour:
in the projectors-view
if the height and width is just right a scrollbar flickers fast.

How to recreate/finde the correct height/width:
The height and width are not the same for each screen
You have to rearrange the height and width manually, meaning not with the mobile-view-tool in the browser.
You need two projectors.
Shrink the width until the projectors almost have to be scrollable
Now make it slightly smaller

The now appearing scrollbar shrinks the available width and hence force the dynamic projectors to shrink themselves.
Because the projectors shrunk they do not need a scrollbar anymore, so the scrollbar vanishes...
Making the width just slightly bigger and allowing the projectors to expand again.
Because the projectors expanded they now need a scrollbar again and the scrollbar appears...
so on and so forth.

Two widths/heights which create this bug for me are:
width:703px height:968px
width:970px height:968px

wanted behaviour:
The screen should not flicker

Start in the projectors-view and reproduce the flicker at 703px × 968px or 970px × 968px by manually resizing the screen with two projectors. Trace the scrollbar and dynamic projector sizing interaction; done means the projectors view remains stable without the scrollbar repeatedly appearing and disappearing.