I use unikey to type Vietnamese and it works fine with openoffice. But when I turn the anaphraseus keyboard on, then I can't type in Vietnamese. How can I fix this?
Yes, Dmitry is right.
Try to change key modifier from Alt to Shift or Ctrl.
Unikey is C++ application to type Vietnamese in X Windows and Windows.
See https://sourceforge.net/projects/unikey for details.
Try changing the key modifier in the setup dialog (sorry, have no idea what is unikey).