As with a lot of Atera, widen the scroll bars, at least when the mouse hovers over if not all the time. Also allow the separator between file structure and content to be movable, a few levels deep and all you can see is ...
And, let the right section (contents) be selectable also, its a very clunky UI and needs reworking to be properly usable. Plus have a allow/deny click box per customer (or folder, or device) to allow the use of it.