Reapplied multihead patch that I backed out. No merge, unfortunately.

cmd/wm/client.c

@@ -128,12 +128,19 @@ update_client_grab(Client *c, Bool is_sel)
 void
 focus_client(Client *c, Bool restack)
 {
-	Client *old = sel_client();
+	Client *old;
-	Frame *f = c->sel;
+	Frame *f;
-	Client *old_in_area = sel_client_of_area(f->area);
+	Client *old_in_area;
-	View *v = f->area->view;
+	View *v;
 	static char buf[256];
 
+	if(!sel_screen)
+		return;
+
+	old = sel_client();
+	f = c->sel;
+	old_in_area = sel_client_of_area(f->area);
+	v = f->area->view;
 	v->sel = f->area;
 	f->area->sel = f;
 	c->floating = (f->area == v->area);
@@ -286,7 +293,7 @@ draw_client(Client *c)
 	d.font = blitzfont;
 	d.gc = c->gc;
 
-	if(c == sel_client())
+	if(sel_screen && (c == sel_client()))
 		d.color = def.sel;
 	else
 		d.color = def.norm;
@@ -323,7 +330,7 @@ draw_client(Client *c)
 	blitz_drawborder(&d);
 	d.rect.x = 0;
 
-	if(c == sel_client())
+	if(sel_screen && (c == sel_client()))
 		d.color = def.sel;
 	else
 		d.color = def.norm;

cmd/wm/event.c

@@ -16,6 +16,7 @@ static void handle_buttonrelease(XEvent * e);
 static void handle_configurerequest(XEvent * e);
 static void handle_destroynotify(XEvent * e);
 static void handle_enternotify(XEvent * e);
+static void handle_leavenotify(XEvent * e);
 static void handle_expose(XEvent * e);
 static void handle_keypress(XEvent * e);
 static void handle_keymapnotify(XEvent * e);
@@ -35,6 +36,7 @@ init_x_event_handler()
 	handler[ConfigureRequest] = handle_configurerequest;
 	handler[DestroyNotify] = handle_destroynotify;
 	handler[EnterNotify] = handle_enternotify;
+	handler[LeaveNotify] = handle_leavenotify;
 	handler[Expose] = handle_expose;
 	handler[KeyPress] = handle_keypress;
 	handler[KeymapNotify] = handle_keymapnotify;
@@ -204,16 +206,27 @@ handle_enternotify(XEvent *e)
 		return;
 
 	if((c = client_of_win(ev->window))) {
-		Client *old = selected_client();
 		Frame *f = c->sel;
 		Area *a = f->area;
 		if(a->mode == Colmax)
 			c = a->sel->client;
-		if(c != old)
+		focus(c, False);
-			focus(c, False);
+	}
+	else if(ev->window == root) {
+		sel_screen = True;
+		draw_clients();
+	}
+}
+
+static void
+handle_leavenotify(XEvent *e)
+{
+	XCrossingEvent *ev = &e->xcrossing;
+
+	if((ev->window == root) && !ev->same_screen) {
+		sel_screen = True;
+		draw_clients();
 	}
-	else if(ev->window == root)
-		XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime); 
 }
 
 static void

cmd/wm/wm.c

@@ -141,6 +141,9 @@ init_cursors()
 static void
 init_screen()
 {
+	Window w;
+	int ret;
+	unsigned mask;
 	XGCValues gcv;
 
 	gcv.subwindow_mode = IncludeInferiors;
@@ -155,6 +158,8 @@ init_screen()
 	rect.width = DisplayWidth(dpy, screen);
 	rect.height = DisplayHeight(dpy, screen);
 	def.snap = rect.height / 63;
+
+	sel_screen = XQueryPointer(dpy, root, &w, &w, &ret, &ret, &ret, &ret, &mask);
 }
 
 /*
@@ -315,7 +320,7 @@ main(int argc, char *argv[])
 	init_lock_keys();
 	init_screen();
 
-	wa.event_mask = SubstructureRedirectMask;
+	wa.event_mask = SubstructureRedirectMask | EnterWindowMask | LeaveWindowMask;
 	wa.cursor = cursor[CurNormal];
 	XChangeWindowAttributes(dpy, root, CWEventMask | CWCursor, &wa);
 

cmd/wm/wm.h

@@ -237,6 +237,7 @@ Atom net_atom[NetLast];
 Cursor cursor[CurLast];
 unsigned int valid_mask;
 unsigned int num_lock_mask;
+Bool sel_screen;
 void (*handler[LASTEvent]) (XEvent *);