Bottom right block

Not sure if this is a known:If you use a bigger than 1x1 block selector (2x2 or 3x2) in ordering pixels and you scroll right down, firstly you can select pixels outside the wall to the right by selecting pixels in the rightmost column (then the top left of the block is in the rightmost column and the rightmost pixels in the block are outside the wall). These can be deselected though.If you do this right at the bottom of the wall so that the first block to the right of the wall in the last row is selected, you can't deselect it (or I can't).It could be an artefact of the size of my background image but I think I've been careful to size it correctly.rgdsCaroline