diff --git a/dbus-examples/inverter.sh b/dbus-examples/inverter.sh
index eb2df58..612579c 100644
--- a/dbus-examples/inverter.sh
+++ b/dbus-examples/inverter.sh
@@ -1,6 +1,20 @@
 #!/bin/sh
 
-#TODO: Check compton running; Check dbus interface available
+# === Verify `compton --dbus` status === 
+
+if [ -z "`dbus-send --session --dest=org.freedesktop.DBus --type=method_call --print-reply /org/freedesktop/DBus org.freedesktop.DBus.ListNames | grep compton`" ]; then
+  echo "compton DBus interface unavailable"
+  if [ -n "`pgrep compton`" ]; then
+    echo "compton running without dbus interface"
+    #killall compton & # Causes all windows to flicker away and come back ugly.
+    #compton --dbus & # Causes all windows to flicker away and come back beautiful
+  else
+    echo "compton not running"
+  fi
+  exit 1;
+fi
+
+# === Setup sed ===
 
 if [ -z "$SED" ]; then
   SED="sed"
@@ -18,34 +32,36 @@ fi
 
 service="com.github.chjj.compton.${dpy}"
 interface="com.github.chjj.compton"
-object='/com/github/chjj/compton'
+compton_dbus="dbus-send --print-reply --dest="${service}" / "${interface}"."
 type_win='uint32'
 type_enum='uint16'
 
 # === Color Inversion ===
 
-# Ensure we are tracking focus
-dbus-send --print-reply --dest="$service" "$object" "${interface}.opts_set" string:track_focus boolean:true &
-
-# Get window ID of currently focused window
-focused=$(dbus-send --print-reply --dest="$service" "$object" "${interface}.find_win" string:focused | $SED -n 's/^[[:space:]]*'${type_win}'[[:space:]]*\([[:digit:]]*\).*/\1/p')
-
-if [ -n "$focused" ]; then
-  # Get invert_color_force property of the focused window
-  color=$(dbus-send --print-reply --dest="$service" "$object" "${interface}.win_get" "${type_win}:${focused}" string:invert_color_force | $SED -n 's/^[[:space:]]*'${type_enum}'[[:space:]]*\([[:digit:]]*\).*/\1/p')
-  # Set the window to have inverted color
-  case "${color}" in
-    0)
-      # Set the window to have inverted color
-      dbus-send --print-reply --dest="$service" "$object" "${interface}.win_set" "${type_win}:${focused}" string:invert_color_force "${type_enum}:1" &
-    ;;
-    *) # Some windows have invert_color_force == 2
-      # Set the window to have normal color
-      dbus-send --print-reply --dest="$service" "$object" "${interface}.win_set" "${type_win}:${focused}" string:invert_color_force "${type_enum}:0" &
-    ;;
-  esac
+# Get window ID of window to invert
+if [ -z "$1" ] || [ "$1" = "selected" ]; then
+  window=$(xwininfo -frame | sed -n 's/^xwininfo: Window id: \(0x[[:xdigit:]][[:xdigit:]]*\).*/\1/p') # Select window by mouse
+elif [ "$1" = "focused" ]; then
+  # Ensure we are tracking focus
+  ${compton_dbus}opts_set string:track_focus boolean:true &
+  window=$(${compton_dbus}find_win string:focused | $SED -n 's/^[[:space:]]*'${type_win}'[[:space:]]*\([[:digit:]]*\).*/\1/p') # Query compton for the active window
+elif [ -n "$(${compton_dbus}list_win | grep "$1")" ]; then
+  window="$1"
 else
-  echo "Cannot find focused window."
+  echo "$0" "[ selected | focused | window-id ]"
+  exit 1;
+fi
+
+# Color invert the selected or focused window
+if [ -n "$window" ]; then
+  if [ "$(${compton_dbus}win_get "${type_win}:${window}" string:invert_color_force | $SED -n 's/^[[:space:]]*'${type_enum}'[[:space:]]*\([[:digit:]]*\).*/\1/p')" -eq 0 ]; then
+    invert=1 # Set the window to have inverted color
+  else
+    invert=0 # Set the window to have normal color
+  fi
+  ${compton_dbus}win_set "${type_win}:${window}" string:invert_color_force "${type_enum}:${invert}" &
+else
+  echo "Cannot find $1 window."
   exit 1;
 fi
 exit 0;