Stills rendering window not showing controls and badly lagging

[Reindeer]

Running the trial version of 13 on a Mac, when I press ctrl-R to render a still, the content doesn't automatically fit the window. I usually can only see a detail of the total image. I try to zoom out but the zooming slider is invisible, tucked away somehow in the render window's lower side.
If I put the pointer on this lower side I can somehow 'grab' an invisible slider, so to speak. But the zooming is terribly slow (Mac's spinning beach ball).
This was already happening in Moho 12.5 but to a lesser degree because the controls were a TINY bit visible and if I could move them it didn't seem to have so much trouble zooming. This makes rendering still images (whether using vector or bitmap) completely impossible.
I don't know if this is just a flaw in the Mac version, or a flaw in MY Mac's version... but it's definitely there.

[Reindeer]

Update: altough the UI is hiding the zoom slider, I can zoom out by using a two finger swipe on the trackpad. It's still quite laggy, especially when zooming in. The image I'm zooming is nothing complex, no color, gradients, softened edges. Just a few test doodle lines with a couple of brushes.