With a relatively large script open, selecting objects in the explorer window is insanely slow. This also applies to selecting anything else in Studio- options in Find All, focusing on the script window, double clicking on Scripts starts renaming rather than opening, etc.
In this video you can see I am selecting things just fine with the script tabbed out (open script tabs didn’t get captured) but as soon as I open my long script (around 1,000 lines) things begin to slow down.
This only starts to happen after I have had Studio open for a few hours, have not used Play Solo in this Studio session.
My Studio version is 0.442.3.409454 running in Windows 10 Pro v1909