Move Toolbar Separator

I have created a custom toolbar and associated icons and separators. I would like to move a separator, but there doesn’t seem to be a way to do it. I can move icon buttons with the shift-drag method, but that doesn’t work for separators. The following page doesn’t give any guidance either.
http://docs.mcneel.com/rhino/5/help/en-us/user_interface/using_toolbars.htm

Hello - it should work, but it is indeed hard to click on just the right spot to grab one of these things. The tip of the cursor arrow needs to be right on the line when you mouse-down with Shift.

-Pascal