I'm experiencing a problem that appears very similar to this one, and I can add a bit of information.
Summary: When I have scim+anthy installed as an input method, the call to XOpenIM fails, returning a null pointer. But I don't know much about the internals of X, so can't be 100% sure this is the root of the problem. Nor do I know what to look at next. My environment: up to date Arch Linux, dmenu 4.9. For X input methods, using scim and anthy by setting environment variables: export XMODIFIERS=@im=SCIM export GTK_IM_MODULE=scim export QT_IM_MODULE=scim To reproduce the crash, I can do printf 'foo\nbar' | dmenu and then press return. With the Arch Linux 4.9, this produces a segmentation fault. After I downgraded to the Arch version of dmenu 4.8, it works correctly. So I downloaded the 4.9 source code and built it myself, with no changes to config.mk or anything else. This version produces still produces the segfault. Then I added debugging code to print some information to stderr. From this, I see that the crash seems to be inside XmbLookupString, as reported previously; the xic pointer returned from XCreateIC and passed to XmbLookupString is null, and the xim pointer returned from XOpenIM and passed to XCreateIC is also null. After this, I restarted X with scim disabled by commenting out the exports mentioned above, and retried the printf into dmenu. Now it works correctly, and reports that both XOpenIM and XCreateIC return non-null pointers. I'm not sure what to look at next, so I hope that helps someone else to diagnose the problem...
