diff --git a/debian/ibus-mozc-gnome-initial-setup.sh b/debian/ibus-mozc-gnome-initial-setup.sh
index 5dcd372..023d54d 100755
--- a/debian/ibus-mozc-gnome-initial-setup.sh
+++ b/debian/ibus-mozc-gnome-initial-setup.sh
@@ -1,19 +1,31 @@
 #!/bin/sh
 
+# If ibus-mozc is removed but not purged, keep hands off :-)
 dpkg-query -l ibus-mozc 2>/dev/null | grep -q ^ii || exit 0
+
+# If non-ibus IM framework is set-up (by im-config etc.), keep hands off :-)
 env | grep -E '^(XMODIFIERS|GTK_IM_MODULE|QT_IM_MODULE|CLUTTER_IM_MODULE)=' | grep -q ibus || exit 0
+
 mkdir -p ${XDG_DATA_HOME:-~/.local/share}
 exec >> ${XDG_DATA_HOME:-~/.local/share}/ibus-mozc-gnome-initial-setup.log 2>&1
-key=/org/gnome/desktop/input-sources/sources;
+
+key=/org/gnome/desktop/input-sources/sources
+
+# Try to read the current value
 for i in $(seq 30); do
 	value=$(dconf read $key)
 	[ x != x"$value" ] && break; sleep 1
 done
+[ x != x"$value" ] || { echo "E: dconf read failed"; exit 1; }
 
-[ x != x"$value" ] || { echo "E: dconf read failed"; exit 1; }
-( echo "$value" | \
-	grep -F "('ibus', " && { echo "I: GNOME ibus already set-up. Doing nothing. Current: $value"; exit 0; }; \
-	echo "I: Current: $value"; \
-	value="[('ibus', 'mozc-jp'), ${value#[}"; \
-		dconf write $key "$value" || { echo "E: dconf write failed. New: $value"; exit 1; }; \
-	echo "I: Done. New: $value" ) && touch ${XDG_CONFIG_HOME:-~/.config}/ibus-mozc-gnome-initial-setup-done
+# Try to write the new value
+(
+	# If some ibus input method is already used, keep hands off :-)
+	echo "$value" | grep -F "('ibus', " && { echo "I: GNOME ibus already set-up. Doing nothing. Current: $value"; exit 0; }
+
+	echo "I: Current: $value"
+
+	value="[('ibus', 'mozc-jp'), ${value#[}"
+	dconf write $key "$value" || { echo "E: dconf write failed. New: $value"; exit 1; }
+	echo "I: Done. New: $value"
+) && touch ${XDG_CONFIG_HOME:-~/.config}/ibus-mozc-gnome-initial-setup-done