This may already be somewhere on here, I didn't see it. I missed being able to view all posts quickly from within a thread, in UBB 7.1. You can click on "All" in postlist, but if you jump into the middle of a thread via search results or something, there's no easy way.
So here's a quick and dirty mod for UBB 7.1b5:
In ubbthreads.inc.php:
find (around line 1457):

Add BELOW it:

(I comment all my hacks/mods so that I can do a global search for "hack" and see what I've done when I update or whatever. Change the comment lines to whatever you want.)

Nice, thank you for sharing

Always a good idea - everyone should do this IMHO

I like it; perhaps make a request to Rick to make it official

it should be noted that this will add an "All" entry to everywhere that paginates things, even where not applicable

Could be kinda fun

D'oh! That does make it kinda dirty, but I ran into situations where I needed it in showflat so often that it's worth it to me for now.

would be better if you modified the function to take an optional argument called "$show_all_link" and default it to false, then modify showflat.inc.php, showthreaded.inc.php, etc to pass true as the third parameter

That would require an actual knowledge of php/programming, ha ha. I'm completely self-taught by viewing source on stuff for the last 5 years or so, so my knowledge is sorely lacking in some very basic areas. Sigh.