Slow invisibility

Setting text to be invisible seems to mean terribly slow scrolling in xemacs, if the invisible area is large AND there are a lot of extents (e.g. from font-locking) in the invisible area. An example: Open a reasonably big file (redisplay.c will do), and go to the beginning of the buffer. Make sure font-lock-mode is on. Say M-: (put-text-property (+ (point) 2000) (+ (point) 200000) 'invisible t) Scroll forward and backward a couple of time. And voila: xemacs seems to hang for quite a while (at least it does on my machine, on both cygwin and mingw builds of latest cvs). I don't know even remotely enough to track this down, but gprof seems to say that create_text_block in redisplay.c is spending a lot of time. There seems to be a check there for data.ef->invisible, that if true steps forward to the next character - instead of going to the end of the invisible extent. If selective display is on, on the other hand, it makes a search directly for the end of line (which seems to be the reasonable thing to do - but as I said, I really don't know this...). Anyway, it would be very good to have invisibility as an alternative to selective display in xemacs (in outline-mode etc.), as in the latest fsfmacs. Something to look into for someone who knows...? /dan -- Dan Ola Holmsand Innehållsbolaget dan(a)innehall.com