The fixed group header in the Multiselect Box is an awesome feature. 
But in some cases it is more confusing than helpfull. 
In those cases it should be possible the use grouping without the Fixed Group Header. 
At the time of writing (2017 Q1) this is only possible with a workaround. It would be awesome if this behaviour could be possible without the databound function. 


Example of the 'problem' and the workaround:
http://dojo.telerik.com/OkUhE/5