the SelectionGrid is currently a boolean value (0: no grid / 1: 9 cells grid)
I always use the 9 cells grid because it helps me much!
but it would be much more comfortable to have alternate patterns for the SelectionGrid like a 100 cells grid, a 2 diagonal lines (crossing showing the center of the picture), ... and even a fibonacci spiral for cropping according to the Golden ratio.
if this is implemented, it would be user-friendly to be able to change the pattern(s) for the SelectionGrid while selection is active, using a shortcut
.