When switching between windows, and Revit TABs, I've found that the TABs do not roll-over.
Example, open new project, place anything in the view, switch between TABs on ribbon, then switch to open window side-by-side for properties or browser, then back to ribbon TABs. The TABs remain LOCKED until you pick on drawing area so that you can unlock TABs and switch between TABs on Ribbon.
