Maybe I'm missing something here but in my "Assets Pane", media and blocks are displayed below each other instead of side-by-side.
Is this the desired behavior or can I adjust them so that they're next to each other?
At least this seems to be the case in the "EPiServer User interface Manual": http://webhelp.episerver.com/latest/getting-started/user-interface.htm
Also, "EPiserver.CMS.UI" and "EPiServer.CMS.UI.Core" are both running 9.9.2.
Try resetting your views. Go to My Settings -> Display options
That did the trick.