Have you tried to restore a previous database backup from just before the install to see if it brings your compatibilities back? I'll be curious to see what mine looks like, but away from that computer right now.
Whoops. Looks like one of our controls was having a fit switching 'to' the eBay Categories tab. We got that fixed for the next beta, but I think I have a feasible work around for until we get that beta build out though.
If you move your eBay Categories tab to be visible when you save your item window layout, it should start loading better for you. The action of switching to the tab is what causes that slowness so this will eliminate that step. It doesn't seem to have any trouble loading when it's visible on startup of the Item Window.
Would that I could. Sadly there's a fine line between what's possible to modify in those controls and what isn't. We get a bunch of controls from different companies so behavior for the most part is left to the mercy of their judgement.
So in other words, we can tell our program to defer processing on the category bar (what we had to do to fix the loading issue), but we can't easily control how the control is laid out, like whether you can scroll or not.
On the other hand the scrollbar could be saving some users from having their history go off the screen so for them it might be beneficial. Quite the balancing act, this stuff.
Is there an ETA as to when the new build will be out? Our users are also reporting various issues which might be tied to the issue you are describing. We wanted to test out the new build ASAP to see if the issue is related or not.