diff --git a/platform/CXWindowsClipboard.cpp b/platform/CXWindowsClipboard.cpp
index f894789b..08cb1f98 100644
--- a/platform/CXWindowsClipboard.cpp
+++ b/platform/CXWindowsClipboard.cpp
@@ -800,7 +800,7 @@ CXWindowsClipboard::insertReply(CReply* reply)
 	if (newWindow) {
 		// note errors while we adjust event masks
 		bool error = false;
-		CXWindowsUtil::CErrorLock lock(&error);
+		CXWindowsUtil::CErrorLock lock(m_display, &error);
 
 		// get and save the current event mask
 		XWindowAttributes attr;
@@ -852,7 +852,7 @@ CXWindowsClipboard::pushReplies(CReplyMap::iterator mapIndex,
 	// if there are no more replies in the list then remove the list
 	// and stop watching the requestor for events.
 	if (replies.empty()) {
-		CXWindowsUtil::CErrorLock lock;
+		CXWindowsUtil::CErrorLock lock(m_display);
 		Window requestor = mapIndex->first;
 		XSelectInput(m_display, requestor, m_eventMasks[requestor]);
 		m_replies.erase(mapIndex);
@@ -926,7 +926,7 @@ CXWindowsClipboard::sendReply(CReply* reply)
 		log((CLOG_DEBUG1 "clipboard: sending failure to 0x%08x,%d,%d", reply->m_requestor, reply->m_target, reply->m_property));
 		reply->m_done = true;
 		if (reply->m_property != None) {
-			CXWindowsUtil::CErrorLock lock;
+			CXWindowsUtil::CErrorLock lock(m_display);
 			XDeleteProperty(m_display, reply->m_requestor, reply->m_property);
 		}
 
@@ -1016,7 +1016,7 @@ CXWindowsClipboard::sendNotify(Window requestor,
 	event.xselection.target    = target;
 	event.xselection.property  = property;
 	event.xselection.time      = time;
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(m_display);
 	XSendEvent(m_display, requestor, False, 0, &event);
 }
 
diff --git a/platform/CXWindowsScreenSaver.cpp b/platform/CXWindowsScreenSaver.cpp
index 89070e3a..f197b88a 100644
--- a/platform/CXWindowsScreenSaver.cpp
+++ b/platform/CXWindowsScreenSaver.cpp
@@ -24,7 +24,7 @@ CXWindowsScreenSaver::CXWindowsScreenSaver(Display* display) :
 	// watch top-level windows for changes
 	{
 		bool error = false;
-		CXWindowsUtil::CErrorLock lock(&error);
+		CXWindowsUtil::CErrorLock lock(m_display, &error);
 		Window root = DefaultRootWindow(m_display);
 		XWindowAttributes attr;
 		XGetWindowAttributes(m_display, root, &attr);
@@ -46,7 +46,7 @@ CXWindowsScreenSaver::CXWindowsScreenSaver(Display* display) :
 CXWindowsScreenSaver::~CXWindowsScreenSaver()
 {
 	// stop watching root for events
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(m_display);
 	Window root = DefaultRootWindow(m_display);
 	XSelectInput(m_display, root, m_rootEventMask);
 }
@@ -179,7 +179,7 @@ CXWindowsScreenSaver::sendNotify(bool activated)
 		event.xclient.data.l[3]    = 0;
 		event.xclient.data.l[4]    = 0;
 
-		CXWindowsUtil::CErrorLock lock;
+		CXWindowsUtil::CErrorLock lock(m_display);
 		XSendEvent(m_display, m_notify, False, 0, &event);
 	}
 }
@@ -202,7 +202,7 @@ CXWindowsScreenSaver::updateXScreenSaver()
 	}
 
 	// find top-level window with m_atomScreenSaverVersion string property
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(m_display);
 	Window root  = DefaultRootWindow(m_display);
 	Window rw, pw, *cw;
 	unsigned int nc;
@@ -224,7 +224,7 @@ CXWindowsScreenSaver::updateXScreenSaver()
 	// see if xscreensaver is active
 	if (m_xscreensaver != None) {
 		bool error = false;
-		CXWindowsUtil::CErrorLock lock(&error);
+		CXWindowsUtil::CErrorLock lock(m_display, &error);
 		XWindowAttributes attr;
 		XGetWindowAttributes(m_display, m_xscreensaver, &attr);
 		setXScreenSaver(!error && attr.map_state != IsUnmapped);
@@ -250,6 +250,6 @@ CXWindowsScreenSaver::sendXScreenSaverCommand(
 	event.xclient.data.l[3]    = 0;
 	event.xclient.data.l[4]    = 0;
 
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(m_display);
 	XSendEvent(m_display, m_xscreensaver, False, 0, &event);
 }
diff --git a/platform/CXWindowsUtil.cpp b/platform/CXWindowsUtil.cpp
index d7b9ba4c..8279d084 100644
--- a/platform/CXWindowsUtil.cpp
+++ b/platform/CXWindowsUtil.cpp
@@ -19,7 +19,7 @@ CXWindowsUtil::getWindowProperty(Display* display, Window window,
 	int actualDatumSize;
 
 	// ignore errors.  XGetWindowProperty() will report failure.
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(display);
 
 	// read the property
 	const long length = XMaxRequestSize(display);
@@ -93,7 +93,7 @@ CXWindowsUtil::setWindowProperty(Display* display, Window window,
 
 	// save errors
 	bool error = false;
-	CXWindowsUtil::CErrorLock lock(&error);
+	CXWindowsUtil::CErrorLock lock(display, &error);
 
 	// how much data to send in first chunk?
 	UInt32 chunkSize = size;
@@ -179,23 +179,31 @@ CXWindowsUtil::propertyNotifyPredicate(Display*, XEvent* xevent, XPointer arg)
 
 CXWindowsUtil::CErrorLock*	CXWindowsUtil::CErrorLock::s_top = NULL;
 
-CXWindowsUtil::CErrorLock::CErrorLock()
+CXWindowsUtil::CErrorLock::CErrorLock(Display* display) :
+	m_display(display)
 {
 	install(&CXWindowsUtil::CErrorLock::ignoreHandler, NULL);
 }
 
-CXWindowsUtil::CErrorLock::CErrorLock(bool* flag)
+CXWindowsUtil::CErrorLock::CErrorLock(Display* display, bool* flag) :
+	m_display(display)
 {
 	install(&CXWindowsUtil::CErrorLock::saveHandler, flag);
 }
 
-CXWindowsUtil::CErrorLock::CErrorLock(ErrorHandler handler, void* data)
+CXWindowsUtil::CErrorLock::CErrorLock(Display* display,
+				ErrorHandler handler, void* data) :
+	m_display(display)
 {
 	install(handler, data);
 }
 
 CXWindowsUtil::CErrorLock::~CErrorLock()
 {
+	// make sure everything finishes before uninstalling handler
+	XSync(m_display, False);
+
+	// restore old handler
 	XSetErrorHandler(m_oldXHandler);
 	s_top = m_next;
 }
@@ -203,6 +211,10 @@ CXWindowsUtil::CErrorLock::~CErrorLock()
 void
 CXWindowsUtil::CErrorLock::install(ErrorHandler handler, void* data)
 {
+	// make sure everything finishes before installing handler
+	XSync(m_display, False);
+
+	// install handler
 	m_handler     = handler;
 	m_userData    = data;
 	m_oldXHandler = XSetErrorHandler(
@@ -221,13 +233,14 @@ CXWindowsUtil::CErrorLock::internalHandler(Display* display, XErrorEvent* event)
 }
 
 void
-CXWindowsUtil::CErrorLock::ignoreHandler(Display*, XErrorEvent*, void*)
+CXWindowsUtil::CErrorLock::ignoreHandler(Display*, XErrorEvent* e, void*)
 {
-	// do nothing
+	log((CLOG_DEBUG "ignoring X error: %d", e->error_code));
 }
 
 void
-CXWindowsUtil::CErrorLock::saveHandler(Display*, XErrorEvent*, void* flag)
+CXWindowsUtil::CErrorLock::saveHandler(Display*, XErrorEvent* e, void* flag)
 {
+	log((CLOG_DEBUG "flagging X error: %d", e->error_code));
 	*reinterpret_cast<bool*>(flag) = true;
 }
diff --git a/platform/CXWindowsUtil.h b/platform/CXWindowsUtil.h
index 9e8add53..fefcc92a 100644
--- a/platform/CXWindowsUtil.h
+++ b/platform/CXWindowsUtil.h
@@ -30,9 +30,9 @@ public:
 	class CErrorLock {
 	public:
 		typedef void (*ErrorHandler)(Display*, XErrorEvent*, void* userData);
-		CErrorLock();
-		CErrorLock(bool* errorFlag);
-		CErrorLock(ErrorHandler, void* userData);
+		CErrorLock(Display*);
+		CErrorLock(Display*, bool* errorFlag);
+		CErrorLock(Display*, ErrorHandler, void* userData);
 		~CErrorLock();
 
 	private:
@@ -44,6 +44,7 @@ public:
 	private:
 		typedef int (*XErrorHandler)(Display*, XErrorEvent*);
 
+		Display*		m_display;
 		ErrorHandler	m_handler;
 		void*			m_userData;
 		XErrorHandler	m_oldXHandler;
diff --git a/server/CXWindowsPrimaryScreen.cpp b/server/CXWindowsPrimaryScreen.cpp
index a500e545..1537af18 100644
--- a/server/CXWindowsPrimaryScreen.cpp
+++ b/server/CXWindowsPrimaryScreen.cpp
@@ -617,7 +617,7 @@ CXWindowsPrimaryScreen::selectEvents(Display* display, Window w) const
 	// ignore errors while we adjust event masks.  windows could be
 	// destroyed at any time after the XQueryTree() in doSelectEvents()
 	// so we must ignore BadWindow errors.
-	CXWindowsUtil::CErrorLock lock;
+	CXWindowsUtil::CErrorLock lock(display);
 
 	// adjust event masks
 	doSelectEvents(display, w);