I have created an addin with a toolbar that contains two comboboxes. Does anyone know how to reset the combobox when a selection is made from the other one. For instance, i select an item in combobox1. The selected item is now showing in combobox1. I now select an item in combobox2. The selected item in combobox2 is now showing, but combobox1 also still shows its previous selected item. I would like combobox1 to reset to the initial state when i select an item from combobox2.
Initial Toolbar State:

After Landscape has been selected:

After Portrait has been selected, i want the landscape11x17 to go back to the initial state:

As you can see it is not.