rendering.get_all_ids() returns an array of sequential numbers equal to the length of valid ids.
What was expected:
rendering.get_all_ids() returns an array of valid IDs.
Case:
ID's 1-2, 5-8 are valid.
rendering.get_all_ids() returns 3 and 4, but omits 7 and 8. If I don't check is_valid() then this command causes an error trying to reference 3 and 4.
