Rich-text editing (RTE) in BUGtrack relies on a browser support for the contentEditable feature. In BUGtrack 3.57 we've changed the way we detect the feature and instead of checking your browser against the "known-good" list, we are performing feature support check on the fly.
The editing is now enabled on a variety of desktop browsers including MSIE 6+, FireFox 2+, Opera 9.5+, Safari 3+ and Google Chrome.
As for "pocket" browsers, Safari on the iPhone, while reporting support, does not display the keyboard, preventing user input. On Pocket PCs, the only browser seems to support RTE in Opera Mobile 9.5 currently in beta stage. Other "homebrew" mobile browsers likely will not support RTE due to relative complexity in implementation.
Please note that the browser vendors implemented RTE in its own way and every browser has its own quirks. We have no way to control browser behavior, thus the feature provided "as-is."