Buttons' :hover, :active, and checked background-colors should be different
Created by: iBasit
On v4 - http://v4-alpha.getbootstrap.com/components/buttons/#checkbox-and-radio-buttons
Checkbox button, radio button and toggle button. The state of hover is same as checked. so user cant tell if he unchecked it or is it still checked state. its bit confusing.
If you keep hover, checked and unchecked state different from each other, that will solve the issue.