Regular comboboxes("Item 1", etc.) are not being added to dirtyControls in setParameter. So their channels are being set but this then is not being represented in the GUI. I think I've managed to fix that.
Unless there's a particular reason why you check for comboxes instead of (filetype==snaps). (?)
I've just forked your repo Rory, so I'll make pull requests if I find something else I can fix with my (very, very) limited skills.
RefreshRegularCombo.txt (936 Bytes)