[Bug 30653] Deleting text from richedit controls extremely slow

http://bugs.winehq.org/show_bug.cgi?id=30653

--- Comment #3 from Dan Kegel  2012-05-15 11:13:07 CDT ---
Created attachment 40185
  --> http://bugs.winehq.org/attachment.cgi?id=40185
More careful patch

Dylan suggested taking advantage of the fact that there should only
be one bunch of marked paragraphs.  While implementing that, I noticed
a possible old bug: the original loop used item->member.para.next_para
even on non-paragraphs, which is probably a no-no.
This patch also gets rid of the spurious invaidates,
and if you ask it to with +richedit_check, verifies its assumption
that there is only one bunch of marked paragraphs.