diff --git a/src/gui.c b/src/gui.c
index 292da7c..bf53caa 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -814,7 +814,7 @@
 
 #if defined(FEAT_XIM) && defined(FEAT_GUI_GTK)
 	if (!im_xim_isvalid_imactivate())
-	    emsg(_("E599: Value of 'imactivatekey' is invalid"));
+	    emsg(_(e_value_of_imactivatekey_is_invalid));
 #endif
 	// When 'cmdheight' was set during startup it may not have taken
 	// effect yet.