Blender Git Loki

"Pointer" properties can now be reset to some kind of "default" value
when using the Numpad0 feature to reset properties to their default
values.

While this implementation here is not a full/proper implementation, as
you cannot truly specify a default value for some pointers that may
require something other than NULL (i.e. nothing), this should be good
enough for the vast majority of (editable) cases which are fine if set
to NULL.

This is most noticeable with the Active Keying Set field in the
TimeLine header, where it's now possible to simply use Numpad0 to
clear it instead of using a confusing click+backspace+enter dance to
do the same thing.