Adjusted Sizing, and fixed off-screen motion
Now moves correctly off the right-hand side. It is not actually problem (Previous overlap was because location of an object relates to the centre).

The problem is that the left-hand side has an offset- the location (0,0) is not actually on the edge.
Added note. The extra modifications to the frame size are only actually needed to compensate for the 'margin' problem.
They can be removed once it is fixed.