I don't know if this is a bug or by design for some reason when you have the MaxSelectedItems attribute set and you have TagMode="Single" once you reach the max number of selections allowed you can no longer click in the control and have it dropdown so you can see what you have actually selected. You have to hit the displayed "x" in the control to clear the values in order to have the dropdown list of values appear again.
Does anyone know of a way around this? I know our clients are going to want to actually be able to see what they have selected when they are editing the form values.
Thanks!