grab on the root window, it is correct, all lockers do that

.hgtags

@@ -2,3 +2,4 @@
 da5cb1f0a685258d5315ea109860bacbc2871a57 0.2
 f9157b1864388ad8f1920e5fde7c5849e73d8327 0.3
 4c2cf4d6a2d0e08cbe280ec50ef76c9aecfc0fbe 0.4
+bd24ea7fcca26b161225c464df23ecbfe85280e1 0.5

config.mk

@@ -1,5 +1,5 @@
 # slock version
-VERSION = 0.5
+VERSION = 0.6
 
 # Customize below to fit your system
 

slock.c

@@ -81,21 +81,20 @@ main(int argc, char **argv) {
 	w = XCreateWindow(dpy, root, 0, 0, DisplayWidth(dpy, screen), DisplayHeight(dpy, screen),
 			0, DefaultDepth(dpy, screen), CopyFromParent,
 			DefaultVisual(dpy, screen), CWOverrideRedirect | CWBackPixel, &wa);
-
 	XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);
 	pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
 	invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
 	XDefineCursor(dpy, w, invisible);
 	XMapRaised(dpy, w);
 	for(len = 1000; len; len--) {
-		if(XGrabPointer(dpy, w, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
+		if(XGrabPointer(dpy, root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 			GrabModeAsync, GrabModeSync, None, invisible, CurrentTime) == GrabSuccess)
 			break;
 		usleep(1000);
 	}
 	if((running = running && (len > 0))) {
 		for(len = 1000; len; len--) {
-			if(XGrabKeyboard(dpy, w, True, GrabModeAsync, GrabModeAsync, CurrentTime)
+			if(XGrabKeyboard(dpy, root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
 				== GrabSuccess)
 				break;
 			usleep(1000);