>> But the general idea is to enable having a lock state but without it adding such a high impact to the UI
>>as a whole additional column would bring. Locking is not switched around as frequently so it would be good
>>to have it but in some kind of subordinate way.


Change the text to red (or greyed out) if the layer is locked? Keeps it separate from the hide/show side of things


But if you want to use the icon then for this control I think you you need more states of icon.

So you need:

Hidden but not locked - blank
Shown but not locked - eye
Hidden and locked - blank with small lock symbol in corner
Shown and locked - eye with small lock symbol in corner

I've used this technique before in a number of icons - works pretty well

Normal/right click can hide and show, CNTRL + normal/right click locks/unlocks. I would also suggest having have both hide and lock commands on the flyout too for those that just want to use mouse or tablet without resorting to the keyboard


Another tuppence worth from me for your consideration ;-)