on screen scroll button to dynamically zoom in/out to selected (as in SmartDraw), not simply ''zoom to selected'' which is a fixed value

ZoomToSelected fills the screen with selected object, but oftentimes you need to then zoom out a bit, to get some more ''context'' as it were. A slider might appear when hitting zoom to selected, first zooming to selected, then, keeping object selected, moving the slider dynamically soomz in out of object, giveing control of how much adjacent objjects are soomed to too, toodel doo