diff --git a/lib/synergy/CKeyState.cpp b/lib/synergy/CKeyState.cpp
index c5c75007..41a859d9 100644
--- a/lib/synergy/CKeyState.cpp
+++ b/lib/synergy/CKeyState.cpp
@@ -39,7 +39,7 @@ void
 CKeyState::setKeyDown(KeyButton button, bool down)
 {
 	button &= kButtonMask;
-	updateKeyState(button, button, down);
+	updateKeyState(button, button, down, false);
 }
 
 void
@@ -149,7 +149,7 @@ CKeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button)
 	fakeKeyEvents(keys, 1);
 
 	// note that key is down
-	updateKeyState((KeyButton)(button & kButtonMask), localID, true);
+	updateKeyState((KeyButton)(button & kButtonMask), localID, true, true);
 }
 
 void
@@ -230,7 +230,7 @@ CKeyState::fakeKeyUp(KeyButton button)
 	fakeKeyEvents(keys, 1);
 
 	// note that key is now up
-	updateKeyState(button, localID, false);
+	updateKeyState(button, localID, false, true);
 }
 
 void
@@ -486,7 +486,8 @@ CKeyState::fakeKeyEvent(KeyButton button, bool press, bool isAutoRepeat)
 }
 
 void
-CKeyState::updateKeyState(KeyButton serverID, KeyButton localID, bool press)
+CKeyState::updateKeyState(KeyButton serverID, KeyButton localID,
+				bool press, bool fake)
 {
 	// ignore bogus keys
 	if (serverID == 0 || localID == 0) {
@@ -510,6 +511,16 @@ CKeyState::updateKeyState(KeyButton serverID, KeyButton localID, bool press)
 			// never report half-duplex keys as down
 			if (isHalfDuplex(mask)) {
 				m_keys[localID] &= ~kDown;
+				// half-duplex keys on the primary screen don't send the
+				// usual press/release pairs but instead send the press
+				// when toggling on and the release when toggleing off.
+				// since we normally toggle our shadow state on the press
+				// we need to treat the release as a press on the primary
+				// screen.  we know we're on the primary screen if fake is
+				// false.  secondary screens always get press/release pairs.
+				if (!fake) {
+					press = true;
+				}
 			}
 
 			// toggle on the press
diff --git a/lib/synergy/CKeyState.h b/lib/synergy/CKeyState.h
index 00c28eb4..a003b78a 100644
--- a/lib/synergy/CKeyState.h
+++ b/lib/synergy/CKeyState.h
@@ -152,7 +152,7 @@ private:
 	void				fakeKeyEvents(const Keystrokes&, UInt32 count);
 	void				fakeKeyEvent(KeyButton, bool press, bool isAutoRepeat);
 	void				updateKeyState(KeyButton serverID,
-							KeyButton localID, bool press);
+							KeyButton localID, bool press, bool fake);
 
 private:
 	enum {
diff --git a/lib/synergy/CScreen.cpp b/lib/synergy/CScreen.cpp
index 0323d8a8..c7543645 100644
--- a/lib/synergy/CScreen.cpp
+++ b/lib/synergy/CScreen.cpp
@@ -469,7 +469,10 @@ CScreen::enterSecondary(KeyModifierMask toggleMask)
 void
 CScreen::leavePrimary()
 {
-	// do nothing
+	// we don't track keys while on the primary screen so update our
+	// idea of them now.  this is particularly to update the state of
+	// the toggle modifiers.
+	m_screen->updateKeys();
 }
 
 void