This fixes a usability problem where it was hard to tell whether or not a focused and toggleable button was toggled because the focus color would always show unless another button took the focus. This also does the following:
- Improves the look of hover effects on buttons and helps to distinguish hovered toggle buttons from hovered normal buttons.
- Removes the diagonal movement when buttons are sunken. It is now unnecessary and always seemed odd to me.
- Removes the gradient on buttons. The breeze widget style rarely uses gradients and I didn't like how it messed with the button colors.
This patch should probably be landed alongside other patches that introduce a similar focus state style.