The mouse cursor change is done thru the mouse driver software. It normally is a call to a function to load a specific pattern, and that pattern can be user supplied or a default within the mouse driver. Examples of default mouse patterns (shape) are: text mode cursor, hand cursor, arrow pointer, hourglass, etc. The effect you need/want could be made, even when I have never seen an application doing what you say. Out of my mind I can only conceive an app that would monitor the memory area where the current mouse shape is stored and take action if that particular shape changed. I would need to consult tech documents regarding this, but I believe it could be possible. I would not give a definitive answer until I can verify for this.