The default settings in /usr/X11R6/lib/X11/locale/iso8859-1/Compose make Control+Shift+T act like a Multi_key. This is really not needed since you can use only the Multy_key bindings and actually assign any key you want to Multi_key. I encountered this problem while playing with my Emacs configuration, and discussed it with Emacs' developers. It seems like this problem originates in X itself since I saw the same problem with the default files on Solaris. (I also mailed the XFree86 list but got no response so far).
I really do not know much about that stuff. Can you suggest a proper fix, and perhaps attach a patch file, or something and I can run it by some other developers and possibly include it in a future release?
I've looked in to this and I now know the file layouts partially, but am still not completely certain what if anything to change as i do not use any of this stuff at all and I don't want to break it. Tis a side effect of being unilingual and using the default en_US layouts with no special needs. ;o) I will try to dig into this, but please try to explain the problem a little more detailed to me.
Well, I also use just the standard isso8859-1 - which is what originated the problem... The thing is that this file has definitions for key combinations to get all kinds of accented characters etc. Actually, it has three parts - one with Multi_key, a quick thing with dead_acute and the last part is almost an exact copy of the Multi_key thing with Ctrl<T> instead. Now this thing makes it possible to get accented keys with C-S-t, which is bogus since you have bindings for Multi_key anyway - so if you realy want to use C-S-t, you can use your .xmodmap or whatever to modify it so it produces a Multi_key, and this will be an identical thing. So what I suggest is just killing the whole Ctrl<T> section, I don't expect anyone to really use it. One reason I can say that last sentence is that from digging around I learned that once the French Compose file had the same binding for C-S-t, but it was removed. Funny that only the English one is the one left with this junk...
Ok, I think I get the idea now. I will see what i can squeeze it into my next build.
Ok, I've added it to 4.0.3-11