diff --git a/Source/WindowControllers/ctlPrefWindow.swift b/Source/WindowControllers/ctlPrefWindow.swift
index 26decb55..161ed061 100644
--- a/Source/WindowControllers/ctlPrefWindow.swift
+++ b/Source/WindowControllers/ctlPrefWindow.swift
@@ -240,6 +240,7 @@ class ctlPrefWindow: NSWindowController {
   }
 
   @IBAction func updateIMKCandidateEnableStatusAction(_: Any) {
+    NSLog("vChewing App self-terminated due to enabling / disabling IMK candidate window.")
     NSApplication.shared.terminate(nil)
   }
 
diff --git a/Source/WindowNIBs/Base.lproj/frmPrefWindow.xib b/Source/WindowNIBs/Base.lproj/frmPrefWindow.xib
index 5d59da3c..26169615 100644
--- a/Source/WindowNIBs/Base.lproj/frmPrefWindow.xib
+++ b/Source/WindowNIBs/Base.lproj/frmPrefWindow.xib
@@ -1111,7 +1111,6 @@ Features listed here may not work as expected.</string>
                         <font key="font" metaFont="cellTitle"/>
                     </buttonCell>
                     <connections>
-                        <action selector="updateIMKCandidateEnableStatusAction:" target="-2" id="dAG-Si-cta"/>
                         <binding destination="32" name="value" keyPath="values.AdjustIMKCandidateWindowLevel" id="E6Z-Rn-IHD"/>
                         <binding destination="32" name="enabled" keyPath="values.UseIMKCandidateWindow" id="qla-KO-plC"/>
                     </connections>