[Blindness] Canvas is partly redrawn under the toolbar

[Karl DD]

After the toolbar is hidden, the area directly underneath is redrawn even though the 'Blindness' module is activated.

This is a side effect of holding back drawing of the screen despite the shapes drawn being committed. As the toolbar is overlaid on the canvas something has to be redrawn there after it 'disappears' - in this case the updated canvas. Need some way to save the canvas and then redraw it.

[Karl DD]

This has been resolved in the Alpha 002 release.