diff --git a/Unshaky/Info.plist b/Unshaky/Info.plist
index a6cb920..7dc2947 100644
--- a/Unshaky/Info.plist
+++ b/Unshaky/Info.plist
@@ -17,9 +17,9 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.2.2</string>
+	<string>0.2.3</string>
 	<key>CFBundleVersion</key>
-	<string>7</string>
+	<string>8</string>
 	<key>LSMinimumSystemVersion</key>
 	<string>$(MACOSX_DEPLOYMENT_TARGET)</string>
 	<key>LSUIElement</key>
diff --git a/Unshaky/PreferenceViewController.swift b/Unshaky/PreferenceViewController.swift
index 7d4e43e..87e6fdd 100644
--- a/Unshaky/PreferenceViewController.swift
+++ b/Unshaky/PreferenceViewController.swift
@@ -132,6 +132,7 @@ class PreferenceViewController: NSViewController,
                            117:    "ForwardDelete",
                            52:     "Linefeed",
                            53:     "Escape",
+                           54:     "RightCommand",
                            55:     "Command",
                            56:     "Shift",
                            57:     "CapsLock",
diff --git a/Unshaky/ShakyPressPreventer.m b/Unshaky/ShakyPressPreventer.m
index 156aeff..cc1a3f1 100644
--- a/Unshaky/ShakyPressPreventer.m
+++ b/Unshaky/ShakyPressPreventer.m
@@ -58,6 +58,33 @@ - (CGEventRef)filterShakyPressEvent:(CGEventRef)event {
     // ignore unconfigured keys
     if (keyDelays[keyCode] == 0) return event;
     
+    {
+        // handle control, command, option and shift keys
+        CGEventFlags flags;
+        BOOL isModifierPressed;
+        switch (keyCode) {
+            case 54: // RightCommand
+            case 55: // Command
+            case 56: // Shift
+            case 58: // Option
+            case 59: // Control
+            case 60: // RightShift
+            case 61: // RightOption
+            case 62: // RightControl (this key does not exist on MacBook Pro's keyboard)
+            case 63: // Function
+                flags = CGEventGetFlags(event);
+                isModifierPressed = (flags & (kCGEventFlagMaskAlternate | kCGEventFlagMaskCommand | kCGEventFlagMaskControl | kCGEventFlagMaskShift | kCGEventFlagMaskSecondaryFn)) > 0;
+                if (isModifierPressed)
+                    eventType = kCGEventKeyDown;
+                else
+                    eventType = kCGEventKeyUp;
+                break;
+                
+            default:
+                break;
+        }
+    }
+    
     if (lastPressedTimestamps[keyCode] == 0.0) {
         lastPressedTimestamps[keyCode] = [[NSDate date] timeIntervalSince1970];
         lastPressedEventTypes[keyCode] = eventType;
@@ -92,7 +119,7 @@ - (CGEventRef)filterShakyPressEvent:(CGEventRef)event {
 
 - (BOOL)setupInputDeviceListener {
     
-    CGEventMask eventMask = ((1 << kCGEventKeyDown) | (1 << kCGEventKeyUp));
+    CGEventMask eventMask = ((1 << kCGEventKeyDown) | (1 << kCGEventKeyUp) | (1 << kCGEventFlagsChanged));
     CFMachPortRef eventTap = CGEventTapCreate(kCGSessionEventTap, kCGHeadInsertEventTap, 0,
                                 eventMask, myCGEventCallback, (__bridge void *)(self));
     if (!eventTap) {