If you own Smartphone with dual keyboard (phone-like and QUERTY one), live in country that is not supported with T9 input, you may be annoyed that it cannot be disabled in threaded SMS view. Every other text box remembers whether it is disabled or enabled, but this one will not.
One thing that worked for me is Creating DWORD value named CarrierDefaultTextMode under HKEY_LOCAL_MACHINE\Software\Tegic\eT9\IME and giving it value of 0. This forces phone to ignore language settings and default to multi-press entry.
Also notice that, since we haven't destroyed anything, you can switch to XT9 on per-message basic.
For editing you can use any registry editor out there, but do be careful.