I too was furious about this new change. Its awful and distracting. However I JUST found something that made it a bit more bearable (maybe it will help others too)....
If you edit the menu and add your most frequently visited tabs as a "bookmark" (Mine were Banking, Reports, Reconcile and COA) Then when you click on one of those bookmarks (as opposed to clicking through the menu levels) then the menu stays open and doesn't collapse and do its annoying animation. Just thought I'd pass along to others who have been struggling like I have with this menu redesign.