Visualizing disabled buttons with a lighter shade of grey background is a bit un-androidish and confusing imho. How about leaving background unchanged and using foreground (ie icon & text) with an alpha value of 0x40 or some such?
Can you show an example?
maybe a bit like
(//http://aplud.com/ik3rp.png)
ie background stays the same, foreground (icon and/or text) is painted with alpha blending.
however, i disagree a bit with the idea of disabled toolbar buttons in general. maybe they should be made clever toggles instead.
design of locus changed in last 1.16.0 version a little bit. This affected also a disabled state of buttons. Anyway I'm denied this wish, because current state is just a side effect to this idea