Hi Michael,
please kindly consider the following suggestions re/setting the Viewing controls for A-Z-P-R-R's:
1. Right-click to bring up an enhanced dialog box (also as presently in 'Options') to define Viewing settings;
2. Placement control - not just at bottom of the view-port, but alternatively left or right (very useful for lefties);
3. Speed/acceleration controls for mouse movement, obviously useful for Zoom,Pan & Rotate;
4. Split the Z, P and R icons into clickable-areas (like rings or quadrants) so that double-clicking will either Zoom-in/out-2x the current view, Pan-half-a-screen-up/down/left/right or Rotate the view a predefined-Rotate Angle. For example, double-clicking in a a top-left-quadrant over the Rotate Icon will orbit say 30 degrees diagonally over the model; whereas double-clicking in a a top-left-quadrant over the Pan Icon will slide the view 45 degrees diagonally across the screen. Obviously, dragging whilst hovering over an icon will work gracefully, as-is.

Cheers,

- Diego -

PS I'm still learning MoI but nevertheless loving every second of it.
PS #2 I just did a search on "double-click" and understand you do have quite a, ehm, firm position ;) on this (your post # 46.6 re. Can't fillet this curve). So, obviously, implement this functionality in whole or in part or not, whichever way you deem most fitting to your philosophy. After all, MoI is your brain-child ;)