Recently Jonathan (Pobst) announced that our Winforms became feature complete.
Besides feature completeness, there is another important change in the next mono release. We were not ready for multi byte character input. Since we use X11 for Winforms on Linux, we have to treat multi byte input as special case.
We had some code that handles XIM but that was not for text input support. Since there was no one in the winforms team who lives in multi byte land, we hadn't take care of it.
I was not familiar with those stuff, so it took somewhat long time, but lately I got it practically working. I use scim and Atok X3 (it is one of popular traditional commercial Japanese IM engine), which show different behavior / use of X.
The style is over-the-spot (like .NET) and hence it is not as decent as Gtk (i.e. on-the-spot). Also, it supports only XIM (it would be possible to support better IM frameworks like IIIMF). But for now I'm content with a working international input support.
So if you are living in multi byte land, try the next release or daily build version of mono and feel happy :-)