S4S For Rent Beta (Star Version) running slowly

Hello all! First up, I absolutely love the Sims 4 Studio - it is an invaluable tool, and I am so thankful to everyone who has a part in its creation and maintenance.

I have the latest version of the Windows Beta, and I'm finding it's running quite slowly.

I predominately use S4S to organise my custom content, by opening CC files and exporting the thumbnails.

Since I downloaded the latest version, it seems to load a CC file fairly quickly, and then I can export the thumbnail, but then the option to exit takes a while to be available. I'll try to click the X up in the top right corner, but nothing happens. It used to be immediately responsive.

Is anyone else having issues with the latest version of S4S?