Fcitx can't input word group more than 6 Chinese characters in Dash. Causes a crash if entering to many characters.

I cannot see why it can possibly be dash specific.

What's input method are you using? If you are using google-pinyin, you may have this problem. It is not maintained anymore and you may want to use another one. See[1] (bold text).

[1] http://code.google.com/p/libgooglepinyin/

If it is indeed the case, than this is a bug in libgooglepinyin and it is a WONTFIX.

I have tried google-pinyin and sunpinyin, both have the problem.

I input the same word group in other edit area, both are OK, so I relate the problem to Dash.

Hmm strange, I can confirm this. It is possible because nux has implement its own handling of XIMs, which is most likely where the bug is, so this is possible in both the Dash and Hud.

Sadly this is a confirmed problem in nux, and actually is a much bigger problem then it looks. There is a char text[16] that is storing all the data coming in from the XIM, which you can imagine 6 CJK chars is to large to fit in a char[16].

What makes this problem really bad is if you enter in to many characters and cause a crash by overflowing that buffer....so this needs to be fixed ASAP.

Also the stacktrace for the crash isn't very useful as it crashes on the XNextEvent when flushing the X server... but its caused by not having enough room to store the unicode in GraphicsDisplayX11.cpp when we do the XmbLookupString, then do a Memcpy(m_pEvent->text, buffer, num_char_stored); which is where the num_char_stored is greater then the sizeof m_pEvent->text. (which is also why you can't enter more then 6 CJK chars in fcitx).

Fix committed into lp:nux at revision None, scheduled for release in nux, milestone 4.0.1