During the development of myNotes, I came across a nasty problem on some of the HTC smartphones. When using the QWERTY keyboard, certain keys don’t work at all, they only return a function key instead of the alphanumeric character. For example, when I pressed on U key, instead if return the U character, the key only returned the Arrow Up, that made the focus shift to the previous text box.
The only workaround is enabling multiline input mode on text boxes which requires a lot of navigation back and forth between the data entry window and the full screen editor window.
However after poking around various forums (MSDN, XDA developer, Howard’s, etc), I found out that updating the ROM on the problematic devices to the latest version will usually fix this. It seems that HTC has left a bad implementation of IME on some of their phones. Personally, my HTC SMT 5800 works fine after updating it to the latest ROM from UTStarcom. I also found on XDA Developer forum an unofficial (ie. use it at your own risk) keyboard driver update for HTC Cavalier here.