(Very) minor bug - Flat View toolbar icon

The toolbar icon for FlatView selection changes to show the selected mode. This is good :-

However, if I select 'Off', the icon changes to the 'Grouped' icon instead of the 'Off' icon. Not so good :-

This looks to be down to the button definition. I guess this is part of the DOpus deploy, I certainly didn't write it:-
@toggle:if FLATVIEW=Toggle
@icon:flatviewmixed,FLATVIEW=Mixed
@icon:flatviewmixednofolders,FLATVIEW=MixedNoFolders
@icon:flatviewoff,FLATVIEW=Off

@ifset:FLATVIEW=Mixed
Set FLATVIEW=Off
@ifset:FLATVIEW=Grouped
Set FLATVIEW=On,Mixed
@ifset:else
Set FLATVIEW=On,Grouped