The Change load case toolbar allows you to change the current load case/simulation:

The current load case/simulation is displayed in this toolbar, however you can use the drop-down menu to make another selection from the list.  You can also use the arrow up/down buttons to conveniently step through the available load cases/simulations.

You can configure the toolbar visibility by using the context menu.  Select Configure Browser and go to the Toolbars tab.  Toggle on/off the model toolbar by clicking the Change load case check box.