Assigning an image that is not the default to the Disabled state of a button does not work

Tools team notes: Make disabled state hidden.

If the user applies an image to the disabled state of a button the button will not reflect this change in game. For example if I were to set the disabled state of the button to use the cross hairs material when in the state of being disabled it will still show as a default grayed out button. The image will not be applied when the button is set to disabled.

1. Open Attached project
2. Click play
3. Notice that the button is the default disabled gray instead of the blue cross that is assigned to it in the widget.