(ORG-8511)
When panning the axis in a graph, three modes are now supported:
- Pan by percent: Default behavior. Every time +/-/Left/Right key is pressed using mouse wheel to scroll once will pan by percent.
- Pan by major ticks: Every time +/-/Left/Right key is pressed using mouse wheel to scroll once will pan to next/previous major ticks.
- Pan by minor ticks: Every time +/-/Left/Right key is pressed using mouse wheel to scroll once will pan to next/previous minor ticks.
After pressing the 
button, or holding down X key to enter panning mode, press the SPACE key to toggle panning mode.