I have a pretty simple scenario where I have 2 RadComboBox controls in a RadGrid EditMode="Popup". Changing the value of one comboBox enables/disables the other, so I handle the server-side OnSelectedIndexChanged event handler (w/ AutoPostBack="true") of the primary combo. This works just fine, but the small problem is that the popup temporarily disappears, similar to a screen flash on a regular postback. Exact same code with EditMode="EditForms" worked with no screen flash. Any way around this?