doc update for 3D mouse interaction changes

documentation/source/mouse_interaction.rst

@@ -39,4 +39,11 @@ The exact set of items available in the menu depends on the contents of the scen
 3D visualizations use the following mouse interaction:
 
 * Left button drag: Rotates the scene around a central point
+* Middle button drag: Pan the scene by moving the central "look-at" point within the x-y plane
+* Middle button drag + CTRL: Pan the scene by moving the central "look-at" point along the z axis
 * Wheel spin: zoom in/out
+* Wheel + CTRL: change field-of-view angle
+
+And keyboard controls:
+
+* Arrow keys rotate around central point, just like dragging the left mouse button