Different color splash in Design and runtime module is of great help to visually know what is open.  Desktop icons for Designer and Runtime module is also a little different, that helps for visual selection. 

When more than one instant of sesame open in design and runtime modes, the open session are displayed in the task bar. Unfortunately, the icon and description of the open sessions  (Sesame Plus - ve...) are the same for all. When you want to get to one of the open sessions, one has to play trial and error game.  I know, I can possibly change the icon, but then visual connection has already been establised for Sesame with this particular icon. If Designer icon could have bluish tinge, it will help differentiate and narrow down guessing.  Just a thought.