After the previous posts about draggable UI objects I built a simple patch for tracking the mouse position and being able to eaily set bounds for a rollover action. This could be used for highlighting objects if desired. Pretty much an extra, not-entirely-necessary feature, though it could be useful for help comments in a tutorial, or possibly to display information about a particular UI object (for example, the settings within a bpatcher, etc.)
With some more effort all the bounding sizes for all objects on the screen could be saved. Then rollovers would be easily trackable (using a cascading series of if statements to determine whether the mouse is within a specific bounding rectangle). One could have panels behind objects that highlight when rolled over, or some other method of showing the rollover (like changing colors of objects).
Combining this with draggable objects would allow a highly customizeable UI that responds to mouse activity.
Wondering if anyone else has built a similar system--I'd like to see what's out there!