With GTK_IM_MODULE=scim, gtk3 applications crash. For example Firefox. Or simple gtk3-demo from gtk3-devel package:

(1) Run gtk3-demo.
(2) Execute "Dialog and Message Boxes" demo by double-clicking on the label in the left panel.
(3) Focus an entry box by clicking in the "Entry 1" entry box in the Dialogs window.

The gtk3-demo crashes here. It happens with scim-1.4.15-1.fc22.x86_64 and gtk3-3.16.6-1.fc22.x86_64.

This was reported to upstream as <https://github.com/scim-im/scim/issues/5>. 


Also updating GTK3 IM modules when updating gtk3 package leads to this error message:

Cannot load module /usr/lib64/gtk-3.0/3.0.0/immodules/im-scim.so: /usr/lib64/gtk-3.0/3.0.0/immodules/im-scim.so: undefined symbol: gdk_x11_drawable_get_xdisplay
/usr/lib64/gtk-3.0/3.0.0/immodules/im-scim.so does not export GTK+ IM module API: /usr/lib64/gtk-3.0/3.0.0/immodules/im-scim.so: undefined symbol: gdk_x11_drawable_get_xdisplay

This was reported to upstream as <https://github.com/scim-im/scim/issues/4>.

Both upstream bug reports claim this upstream commit fixes it:

commit 88fbabed7dc236642021f8263f1b25bf67c6806e
Author: Tz-Huan Huang <tzhuan>
Date:   Fri Oct 24 13:12:32 2014 +0800

    Disable subdir-objects

diff --git a/configure.ac b/configure.ac
index 3d89eb1..f3901ba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -78,7 +78,7 @@ AC_DEFINE_UNQUOTED(GETTEXT_PACKAGE,"$GETTEXT_PACKAGE", [The gettext domain])
 ###########################################################
 
 # Init automake stuff
-AM_INIT_AUTOMAKE([subdir-objects])
+AM_INIT_AUTOMAKE([])
 AM_CONFIG_HEADER([config.h])
 
 # Init libtool

I can confirm the patch fixes it for me.