diff --git a/main.c b/main.c
index c2585d917e15044e4f6814cc6d797adf22ebf2c7..9bc3a4b4f7046bed7c7c1d74d41539febc0e9403 100644
--- a/main.c
+++ b/main.c
@@ -67,6 +67,7 @@ 	wm.running = 1;
 	while(wm.running) {
 		XNextEvent(wm.dpy, &wm.ev);
 
+		XLockDisplay(wm.dpy);
 		switch (wm.ev.type) {
 			case MapRequest:
 				handle_map_request();
@@ -116,6 +117,7 @@ 			case ConfigureRequest:
 				handle_configure_request();
 				break;
 		}
+		XUnlockDisplay(wm.dpy);
 	}
 
 	deinit_window_manager();
diff --git a/manager.c b/manager.c
index 58ee90ab6ea5761d1fa62ceb4f0f8bd7bc353785..f6b46f1d1695edce858f0c930a2e5f8b13f8cecb 100644
--- a/manager.c
+++ b/manager.c
@@ -586,7 +586,11 @@ 	changes.border_width = ev->border_width;
 	changes.sibling = ev->above;
 	changes.stack_mode = ev->detail;
 
+	XErrorHandler old = XSetErrorHandler(ignore_x_error);
 	XConfigureWindow(wm.dpy, ev->window, ev->value_mask, &changes);
+	XSync(wm.dpy, False);
+	XSetErrorHandler(old);
+
 	log_message(stdout, LOG_DEBUG, "ConfigureRequest for 0x%lx (x=%d, y=%d, w=%d, h=%d)", ev->window, ev->x, ev->y, ev->width, ev->height);
 }
 
@@ -594,6 +598,8 @@ // https://tronche.com/gui/x/xlib/events/structure-control/map.html
 void handle_map_request(void) {
 	Window window = wm.ev.xmaprequest.window;
 	if (window == wm.root) return;
+
+	XErrorHandler old = XSetErrorHandler(ignore_x_error);
 
 	// Move window under cursor position and clamps inside the screen bounds.
 	XWindowAttributes check_attr;
@@ -635,6 +641,10 @@ 	// Grab buttons for click-to-focus.
 	grab_buttons(window);
 
 	add_client(window);
+	
+	XSync(wm.dpy, False);
+	XSetErrorHandler(old);
+
 	log_message(stdout, LOG_DEBUG, "Window 0x%lx mapped and grabbed on desktop %d", window, wm.current_desktop);
 	redraw_widgets();
 	update_client_list();
@@ -972,10 +982,10 @@ void handle_button_release(void) {
 	if (wm.start.subwindow != None && (wm.start.state & MODKEY)) {
 		XDefineCursor(wm.dpy, wm.start.subwindow, None);
 
-		// Restore default error handler
-		XSetErrorHandler(NULL);
+		// Restore window manager error handler
+		XSetErrorHandler(x_error_handler);
 
-		log_message(stdout, LOG_DEBUG, "Restored default cursor on window 0x%lx", wm.start.subwindow);
+		log_message(stdout, LOG_DEBUG, "Restored window manager cursor on window 0x%lx", wm.start.subwindow);
 		wm.start.subwindow = None;
 	}
 
diff --git a/switcher.c b/switcher.c
index 949bcef08e4b45418f4a211e1b5faa5a77b32f06..cde8c9073e24d5cc5dafdc1cc61a6bfd5c630d65 100644
--- a/switcher.c
+++ b/switcher.c
@@ -109,7 +109,7 @@ 		// Grab keyboard to catch Alt release (key release)
 		// We grab it on the root window. 
 		XGrabKeyboard(wm.dpy, wm.root, True, GrabModeAsync, GrabModeAsync, CurrentTime);
 
-		// Count clients
+		// Count clients - allocate extra to handle new windows mapping during this process
 		int count = 0;
 		Client *c = wm.clients;
 		while (c) {
@@ -122,7 +122,7 @@ 			end_cycling();
 			return;
 		}
 
-		wm.cycle_clients = malloc(sizeof(Window) * count);
+		wm.cycle_clients = malloc(sizeof(Window) * (count + 10));
 		wm.cycle_count = 0;
 		wm.active_cycle_index = 0;