I am not sure I understand your question, but maybe you are looking for a way to specify, which pixel will be the active one when you do a mouse click. To set the active pixel, swith cto the "Hot Spot" tool and the click the pixel.
Crosshair Cursors
Help me please!
Alright, how would I make a the middle of a crosshair cursor in the edge without making the crosshair getting into 1/4 pieces?