Alot of people seem to prefer having 2 instances of VS open when testing a control. I just use one and add the control  and a web  project to the same solution. That makes it impossible to test designer  code(I open 2 copies of VS at that point) but makes the control auto update whenever you make any changes. Very little re-starting, refreshing or messing with the ToolBar unless I've changed something to the ToolBar info it-self(icon, name, etc).