For this, I put the same icon (toolbar_grid_off.png) on two different buttons.
The first button is for Action 40472: Toggle CC selection follows note selection and the second is for Action 1017: Toggle grid
When the buttons are "off" they both display the correct icon (the first one from toolbar_grid_off.png. So far, so good.
But when the buttons are "on", the first button displays the third image from toolbar_grid_off.png and the second button displays the first image from toolbar_grid_on.png.
I think that that first button is wrongly displayed. Can anyone confirm?