diff --git a/dwm.c b/dwm.c
index 670afbe..b048e77 100644
--- a/dwm.c
+++ b/dwm.c
@@ -1784,10 +1784,18 @@ updategeom(void) {
 	Bool dirty = False;
 
 #ifdef XINERAMA
-	if(XineramaIsActive(dpy)) {
+	int msw, msh;
+	Monitor *m;
+
+	msw = msh = 0;
+	for(m = mons; m; m = m->next) {
+		msw += m->mw;
+		msh += m->mh;
+	}
+
+	if(XineramaIsActive(dpy) && (msw != sw || msh != sh)) {
 		int i, j, n, nn;
 		Client *c;
-		Monitor *m;
 		XineramaScreenInfo *info = XineramaQueryScreens(dpy, &nn);
 		XineramaScreenInfo *unique = NULL;