Re: Bugs in remove-list-of-text-properties and a patch [WAS: before-change-functions called twice at yank]

[Richard Stallman]

    The general idea is:
    Fremove_list_of_text_properties has a for (;;) loop that loops over the
    parts of the interval. It updates the flag `modified' recording if
    changes have been done. To make things work right, we must call
    modify_region before calling remove_properties iff modified == 0, and we
    must call signal_after_change before returning iff modified != 0.

Would you please add that explanation as a comment?
And maybe this one too:

    The before-change-functions are run by modify_region called immediately
    before the changes are done by remove_properties.