As I have stated many times in my blog, the most serious problem of input method in linux world is not input method, but actually the application. That’s why I maintain a page of applications with buggy input method support.
http://fcitx-im.org/wiki/Hall_of_Shame_for_Linux_IME_Support
Actually I haven’t worked hard on reporting bugs to application themselves. But now I decide to help them fix their problems in the future, with more concrete description what theirs bug is.
Recently I tried to fix an input method bug in kate (though a rarely used feature, so don’t worry).
Though I cannot fix code I’m not familiar with (no I really can’t, there are huge monsters like firefox or libreoffice, or emacs, even gtk will look like a small kitty comparing with them), but more accurate description of bug report may help upstream application more.
There is another problem, that I cannot use all applications (for example I only use firefox, so I’m not be able to notice chromium bugs), but normal user can hardly describe a problem accurately, so if anyone found any reproducible problem (yes, this is very important, otherwise there might be no bug or just because of some careless operation) may related to input method, feel free to send it to fcitx@googlegroups.com and I will take a look at it.