diff --git a/config.def.h b/config.def.h
--- a/config.def.h
+++ b/config.def.h
@@ -15,11 +15,11 @@ const char tags[][MAXTAGLEN] = { "1", "2
 const char tags[][MAXTAGLEN] = { "1", "2", "3", "4", "5", "6", "7", "8", "www" };
 Bool initags[LENGTH(tags)] = {[0] = True};
 Rule rules[] = {
-	/* class:instance:title regex	tags regex	isfloating */	/* monitor */
-	{ "Firefox",			"www",		False,		-1 },
-	{ "Gimp",			NULL,		True,		-1 },
-	{ "MPlayer",			NULL,		True,		-1 },
-	{ "Acroread",			NULL,		True,		-1 },
+	/* class:instance:title regex	tags regex	isfloating */
+	{ "Firefox",			"www",		False },
+	{ "Gimp",			NULL,		True },
+	{ "MPlayer",			NULL,		True },
+	{ "Acroread",			NULL,		True },
 };
 
 /* layout(s) */
diff --git a/config.mk b/config.mk
--- a/config.mk
+++ b/config.mk
@@ -15,10 +15,10 @@ LIBS = -L/usr/lib -lc -L${X11LIB} -lX11 
 LIBS = -L/usr/lib -lc -L${X11LIB} -lX11 -lXinerama
 
 # flags
-CFLAGS = -Os ${INCS} -DVERSION=\"${VERSION}\"
-LDFLAGS = -s ${LIBS}
-#CFLAGS = -g -std=c99 -pedantic -Wall -O2 ${INCS} -DVERSION=\"${VERSION}\"
-#LDFLAGS = -g ${LIBS}
+#CFLAGS = -Os ${INCS} -DVERSION=\"${VERSION}\"
+#LDFLAGS = -s ${LIBS}
+CFLAGS = -g -std=c99 -pedantic -Wall -O2 ${INCS} -DVERSION=\"${VERSION}\"
+LDFLAGS = -g ${LIBS}
 
 # Solaris
 #CFLAGS = -fast ${INCS} -DVERSION=\"${VERSION}\"
diff --git a/dwm.c b/dwm.c
--- a/dwm.c
+++ b/dwm.c
@@ -75,6 +75,7 @@ struct Client {
 	Client *snext;
 	Window win;
 	int monitor;
+	int generation;
 };
 
 typedef struct {
@@ -99,16 +100,16 @@ typedef struct {
 	const char *arg;
 } Key;
 
+typedef struct Monitor Monitor;
 typedef struct {
 	const char *symbol;
-	void (*arrange)(void);
+	void (*arrange)(Monitor *m);
 } Layout;
 
 typedef struct {
 	const char *prop;
 	const char *tags;
 	Bool isfloating;
-	int monitor;
 } Rule;
 
 typedef struct {
@@ -116,7 +117,8 @@ typedef struct {
 	regex_t *tagregex;
 } Regs;
 
-typedef struct {
+struct Monitor {
+	int nth;
 	int screen;
 	Window root;
 	Window barwin;
@@ -126,7 +128,7 @@ typedef struct {
 	Bool *prevtags;
 	Layout *layout;
 	double mwfact;
-} Monitor;
+};
 
 /* function declarations */
 void applyrules(Client *c);
@@ -151,7 +153,7 @@ void enternotify(XEvent *e);
 void enternotify(XEvent *e);
 void eprint(const char *errstr, ...);
 void expose(XEvent *e);
-void floating(void); /* default floating layout */
+void floating(Monitor*); /* default floating layout */
 void focus(Client *c);
 void focusin(XEvent *e);
 void focusnext(const char *arg);
@@ -164,7 +166,7 @@ void grabkeys(void);
 void grabkeys(void);
 unsigned int idxoftag(const char *tag);
 void initfont(Monitor*, const char *fontstr);
-Bool isoccupied(Monitor *m, unsigned int t);
+Bool isoccupied(unsigned int t);
 Bool isprotodel(Client *c);
 Bool isvisible(Client *c, Monitor *m);
 void keypress(XEvent *e);
@@ -190,7 +192,7 @@ void tag(const char *arg);
 void tag(const char *arg);
 unsigned int textnw(Monitor*, const char *text, unsigned int len);
 unsigned int textw(Monitor*, const char *text);
-void tile(void);
+void tile(Monitor*);
 void togglebar(const char *arg);
 void togglefloating(const char *arg);
 void toggletag(const char *arg);
@@ -253,6 +255,17 @@ int selmonitor = 0;
 
 //Bool prevtags[LENGTH(tags)];
 
+void
+dump_tagset(char *s, Bool *t)
+{
+	unsigned int i;
+
+	printf("%s: ", s);
+	for(i = 0; i < LENGTH(tags); i++)
+		printf("%s ", t[i] ? "t" : "f");
+	printf("\n");
+}
+
 /* function implementations */
 void
 applyrules(Client *c) {
@@ -260,7 +273,6 @@ applyrules(Client *c) {
 	unsigned int i, j;
 	regmatch_t tmp;
 	Bool matched_tag = False;
-	Bool matched_monitor = False;
 	XClassHint ch = { 0 };
 
 	/* rule matching */
@@ -270,11 +282,6 @@ applyrules(Client *c) {
 			ch.res_name ? ch.res_name : "", c->name);
 	for(i = 0; i < LENGTH(rules); i++)
 		if(regs[i].propregex && !regexec(regs[i].propregex, buf, 1, &tmp, 0)) {
-			if (rules[i].monitor >= 0 && rules[i].monitor < mcount) {
-				matched_monitor = True;
-				c->monitor = rules[i].monitor;
-			}
-
 			c->isfloating = rules[i].isfloating;
 			for(j = 0; regs[i].tagregex && j < LENGTH(tags); j++) {
 				if(!regexec(regs[i].tagregex, tags[j], 1, &tmp, 0)) {
@@ -289,21 +296,36 @@ applyrules(Client *c) {
 		XFree(ch.res_name);
 	if(!matched_tag)
 		memcpy(c->tags, monitors[monitorat(-1, -1)].seltags, sizeof initags);
-	if (!matched_monitor)
-		c->monitor = monitorat(-1, -1);
 }
 
 void
 arrange(void) {
+	static int generation = 0;
+	int m;
 	Client *c;
-
-	for(c = clients; c; c = c->next)
-		if(isvisible(c, &monitors[c->monitor]))
-			unban(c);
-		else
-			ban(c);
-
-	monitors[selmonitor].layout->arrange();
+	Monitor *mon;
+
+	generation++;
+
+	for(m = 0, mon = &monitors[0]; m < mcount; m++, mon++) {
+
+		for(c = clients; c; c = c->next) {
+			if (c->generation != generation) {
+				/* This client not already placed. */
+				if (isvisible(c, mon)) {
+					c->generation = generation;
+					c->monitor = m;
+					unban(c);
+				}
+				else {
+					c->monitor = -1; /* XXX dme: risky? */
+					ban(c);
+				}
+			}
+		}
+		mon->layout->arrange(mon);
+	}
+
 	focus(NULL);
 	restack();
 }
@@ -414,6 +436,7 @@ cleanup(void) {
 	}
 	for(i = 0; i < mcount; i++) {
 		Monitor *m = &monitors[i];
+
 		if(m->dc.font.set)
 			XFreeFontSet(dpy, m->dc.font.set);
 		else
@@ -422,12 +445,12 @@ cleanup(void) {
 		XFreePixmap(dpy, m->dc.drawable);
 		XFreeGC(dpy, m->dc.gc);
 		XDestroyWindow(dpy, m->barwin);
-		XFreeCursor(dpy, cursor[CurNormal]);
-		XFreeCursor(dpy, cursor[CurResize]);
-		XFreeCursor(dpy, cursor[CurMove]);
-		XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime);
-		XSync(dpy, False);
-	}
+	}
+	XFreeCursor(dpy, cursor[CurNormal]);
+	XFreeCursor(dpy, cursor[CurResize]);
+	XFreeCursor(dpy, cursor[CurMove]);
+	XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime);
+	XSync(dpy, False);
 }
 
 void
@@ -571,14 +594,16 @@ drawbar(void) {
 		Monitor *m = &monitors[i];
 		m->dc.x = 0;
 		for(j = 0; j < LENGTH(tags); j++) {
+			Bool occupied = isoccupied(j);
+
 			m->dc.w = textw(m, tags[j]);
 			if(m->seltags[j]) {
 				drawtext(m, tags[j], m->dc.sel);
-				drawsquare(m, sel && sel->tags[j] && sel->monitor == selmonitor, isoccupied(m, j), m->dc.sel);
+				drawsquare(m, sel && sel->tags[j] && sel->monitor == m->nth, occupied, m->dc.sel);
 			}
 			else {
 				drawtext(m, tags[j], m->dc.norm);
-				drawsquare(m, sel && sel->tags[j] && sel->monitor == selmonitor, isoccupied(m, j), m->dc.norm);
+				drawsquare(m, sel && sel->tags[j] && sel->monitor == m->nth, occupied, m->dc.norm);
 			}
 			m->dc.x += m->dc.w;
 		}
@@ -594,13 +619,13 @@ drawbar(void) {
 		drawtext(m, stext, m->dc.norm);
 		if((m->dc.w = m->dc.x - x) > bh) {
 			m->dc.x = x;
-			if(sel && sel->monitor == selmonitor) {
+			if(sel && sel->monitor == m->nth) {
 				drawtext(m, sel->name, m->dc.sel);
 				drawsquare(m, False, sel->isfloating, m->dc.sel);
 			}
 			else
-				drawtext(m, NULL, m->dc.norm);
-		}
+				drawtext(m, NULL, m->dc.norm);	
+	}
 		XCopyArea(dpy, m->dc.drawable, m->barwin, m->dc.gc, 0, 0, m->sw, bh, 0, 0);
 		XSync(dpy, False);
 	}
@@ -717,12 +742,12 @@ expose(XEvent *e) {
 }
 
 void
-floating(void) { /* default floating layout */
+floating(Monitor *m) { /* default floating layout */
 	Client *c;
 
 	domwfact = dozoom = False;
 	for(c = clients; c; c = c->next)
-		if(isvisible(c, &monitors[selmonitor]))
+		if(isvisible(c, m))
 			resize(c, c->x, c->y, c->w, c->h, True);
 }
 
@@ -976,11 +1001,11 @@ initfont(Monitor *m, const char *fontstr
 }
 
 Bool
-isoccupied(Monitor *m, unsigned int t) {
+isoccupied(unsigned int t) {
 	Client *c;
 
 	for(c = clients; c; c = c->next)
-		if(c->tags[t] && c->monitor == selmonitor)
+		if(c->tags[t])
 			return True;
 	return False;
 }
@@ -1005,7 +1030,7 @@ isvisible(Client *c, Monitor *m) {
 	unsigned int i;
 
 	for(i = 0; i < LENGTH(tags); i++)
-		if(c->tags[i] && monitors[c->monitor].seltags[i] && c->monitor == selmonitor)
+		if(c->tags[i] && m->seltags[i])
 			return True;
 	return False;
 }
@@ -1049,7 +1074,7 @@ void
 void
 manage(Window w, XWindowAttributes *wa) {
 	Client *c, *t = NULL;
-	Monitor *m = &monitors[selmonitor];
+	Monitor *m;
 	Status rettrans;
 	Window trans;
 	XWindowChanges wc;
@@ -1057,6 +1082,9 @@ manage(Window w, XWindowAttributes *wa) 
 	c = emallocz(sizeof(Client));
 	c->tags = emallocz(sizeof initags);
 	c->win = w;
+
+	c->monitor = selmonitor; /* XXX dme: should use current position rather than selected monitor? */
+	m = &monitors[c->monitor];
 
 	applyrules(c);
 
@@ -1178,7 +1206,7 @@ movemouse(Client *c) {
 
 Client *
 nexttiled(Client *c, Monitor *m) {
-	for(; c && (c->isfloating || !isvisible(c, m)); c = c->next);
+	for(; c && (c->isfloating || (c->monitor != m->nth)); c = c->next);
 	return c;
 }
 
@@ -1428,32 +1456,30 @@ run(void) {
 
 void
 scan(void) {
-	unsigned int i, j, num;
+	unsigned int j, num;
 	Window *wins, d1, d2;
 	XWindowAttributes wa;
-
-	for(i = 0; i < mcount; i++) {
-		Monitor *m = &monitors[i];
-		wins = NULL;
-		if(XQueryTree(dpy, m->root, &d1, &d2, &wins, &num)) {
-			for(j = 0; j < num; j++) {
-				if(!XGetWindowAttributes(dpy, wins[j], &wa)
-				|| wa.override_redirect || XGetTransientForHint(dpy, wins[j], &d1))
-					continue;
-				if(wa.map_state == IsViewable || getstate(wins[j]) == IconicState)
-					manage(wins[j], &wa);
-			}
-			for(j = 0; j < num; j++) { /* now the transients */
-				if(!XGetWindowAttributes(dpy, wins[j], &wa))
-					continue;
-				if(XGetTransientForHint(dpy, wins[j], &d1)
-				&& (wa.map_state == IsViewable || getstate(wins[j]) == IconicState))
-					manage(wins[j], &wa);
-			}
-		}
-		if(wins)
-			XFree(wins);
-	}
+	Monitor *m = &monitors[0];
+
+	wins = NULL;
+	if(XQueryTree(dpy, m->root, &d1, &d2, &wins, &num)) {
+		for(j = 0; j < num; j++) {
+			if(!XGetWindowAttributes(dpy, wins[j], &wa)
+			   || wa.override_redirect || XGetTransientForHint(dpy, wins[j], &d1))
+				continue;
+			if(wa.map_state == IsViewable || getstate(wins[j]) == IconicState)
+				manage(wins[j], &wa);
+		}
+		for(j = 0; j < num; j++) { /* now the transients */
+			if(!XGetWindowAttributes(dpy, wins[j], &wa))
+				continue;
+			if(XGetTransientForHint(dpy, wins[j], &d1)
+			   && (wa.map_state == IsViewable || getstate(wins[j]) == IconicState))
+				manage(wins[j], &wa);
+		}
+	}
+	if(wins)
+		XFree(wins);
 }
 
 void
@@ -1536,17 +1562,18 @@ setup(void) {
 	if (XineramaIsActive(dpy)) {
 		info = XineramaQueryScreens(dpy, &mcount);
 	}
-	mcount = 1;
 	monitors = emallocz(mcount * sizeof(Monitor));
 
 	for(i = 0; i < mcount; i++) {
 		/* init geometry */
 		m = &monitors[i];
-
-		m->screen = i;
-		m->root = RootWindow(dpy, i);
-
-		if (mcount != 1) { // TODO: Xinerama
+		m->nth = i;
+
+		m->screen = DefaultScreen(dpy);
+		m->root = RootWindow(dpy, m->screen);
+
+		if (info) {
+			/* Xinerama */
 			m->sx = info[i].x_org;
 			m->sy = info[i].y_org;
 			m->sw = info[i].width;
@@ -1566,12 +1593,12 @@ setup(void) {
 		memcpy(m->prevtags, initags, sizeof initags);
 
 		/* init appearance */
-		m->dc.norm[ColBorder] = getcolor(NORMBORDERCOLOR, i);
-		m->dc.norm[ColBG] = getcolor(NORMBGCOLOR, i);
-		m->dc.norm[ColFG] = getcolor(NORMFGCOLOR, i);
-		m->dc.sel[ColBorder] = getcolor(SELBORDERCOLOR, i);
-		m->dc.sel[ColBG] = getcolor(SELBGCOLOR, i);
-		m->dc.sel[ColFG] = getcolor(SELFGCOLOR, i);
+		m->dc.norm[ColBorder] = getcolor(NORMBORDERCOLOR, m->screen);
+		m->dc.norm[ColBG] = getcolor(NORMBGCOLOR, m->screen);
+		m->dc.norm[ColFG] = getcolor(NORMFGCOLOR, m->screen);
+		m->dc.sel[ColBorder] = getcolor(SELBORDERCOLOR, m->screen);
+		m->dc.sel[ColBG] = getcolor(SELBGCOLOR, m->screen);
+		m->dc.sel[ColFG] = getcolor(SELFGCOLOR, m->screen);
 		initfont(m, FONT);
 		m->dc.h = bh = m->dc.font.height + 2;
 
@@ -1675,54 +1702,51 @@ textw(Monitor *m, const char *text) {
 }
 
 void
-tile(void) {
-	unsigned int i, j, n, nx, ny, nw, nh, mw, th;
+tile(Monitor *m) {
+	unsigned int j, n, nx, ny, nw, nh, mw, th;
 	Client *c, *mc;
 
 	domwfact = dozoom = True;
 
-	nw = 0; /* gcc stupidity requires this */
-
-	for (i = 0; i < mcount; i++) {
-		Monitor *m = &monitors[i];
-
-		for(n = 0, c = nexttiled(clients, m); c; c = nexttiled(c->next, m))
-			n++;
-
-		for(j = 0, c = mc = nexttiled(clients, m); c; c = nexttiled(c->next, m)) {
-			/* window geoms */
-			mw = (n == 1) ? m->waw : m->mwfact * m->waw;
-			th = (n > 1) ? m->wah / (n - 1) : 0;
-			if(n > 1 && th < bh)
-				th = m->wah;
-			if(j == 0) { /* master */
-				nx = m->wax;
+	nw = nx = ny = 0; /* gcc stupidity requires this */
+
+	for(n = 0, c = nexttiled(clients, m); c; c = nexttiled(c->next, m))
+		n++;
+
+	for(j = 0, c = mc = nexttiled(clients, m); c; c = nexttiled(c->next, m)) {
+		/* window geoms */
+		mw = (n == 1) ? m->waw : m->mwfact * m->waw;
+		th = (n > 1) ? m->wah / (n - 1) : 0;
+		if(n > 1 && th < bh)
+			th = m->wah;
+		if(j == 0) { /* master */
+			nx = m->wax;
+			ny = m->way;
+			nw = mw - 2 * c->border;
+			nh = m->wah - 2 * c->border;
+		}
+		else {  /* tile window */
+			if(j == 1) {
 				ny = m->way;
-				nw = mw - 2 * c->border;
-				nh = m->wah - 2 * c->border;
+				nx += mc->w + 2 * mc->border;
+				nw = m->waw - mw - 2 * c->border;
 			}
-			else {  /* tile window */
-				if(j == 1) {
-					ny = m->way;
-					nx += mc->w + 2 * mc->border;
-					nw = m->waw - mw - 2 * c->border;
-				}
-				if(j + 1 == n) /* remainder */
-					nh = (m->way + m->wah) - ny - 2 * c->border;
-				else
-					nh = th - 2 * c->border;
-			}
-			resize(c, nx, ny, nw, nh, RESIZEHINTS);
-			if((RESIZEHINTS) && ((c->h < bh) || (c->h > nh) || (c->w < bh) || (c->w > nw)))
-				/* client doesn't accept size constraints */
-				resize(c, nx, ny, nw, nh, False);
-			if(n > 1 && th != m->wah)
-				ny = c->y + c->h + 2 * c->border;
-
-			j++;
-		}
-	}
-}
+			if(j + 1 == n) /* remainder */
+				nh = (m->way + m->wah) - ny - 2 * c->border;
+			else
+				nh = th - 2 * c->border;
+		}
+		resize(c, nx, ny, nw, nh, RESIZEHINTS);
+		if((RESIZEHINTS) && ((c->h < bh) || (c->h > nh) || (c->w < bh) || (c->w > nw)))
+			/* client doesn't accept size constraints */
+			resize(c, nx, ny, nw, nh, False);
+		if(n > 1 && th != m->wah)
+			ny = c->y + c->h + 2 * c->border;
+
+		j++;
+	}
+}
+
 void
 togglebar(const char *arg) {
 	if(bpos == BarOff)
@@ -1976,7 +2000,6 @@ monitorat(int x, int y) {
 monitorat(int x, int y) {
 	int i;
 
-	return 0;
 	if(!XineramaIsActive(dpy))
 		return 0;