implement multi-tag selection through button3 click on the specific tag

client.c

@@ -24,7 +24,7 @@ resizetitle(Client *c)
 		c->tw = c->w + 2;
 	c->tx = c->x + c->w - c->tw + 2;
 	c->ty = c->y;
-	if(c->tags[tsel])
+	if(isvisible(c))
 		XMoveResizeWindow(dpy, c->title, c->tx, c->ty, c->tw, c->th);
 	else
 		XMoveResizeWindow(dpy, c->title, c->tx + 2 * sw, c->ty, c->tw, c->th);
@@ -276,7 +276,7 @@ manage(Window w, XWindowAttributes *wa)
 	/* mapping the window now prevents flicker */
 	XMapRaised(dpy, c->win);
 	XMapRaised(dpy, c->title);
-	if(c->tags[tsel])
+	if(isvisible(c))
 		focus(c);
 }
 

draw.c

@@ -109,9 +109,9 @@ drawstatus()
 		dc.x += dc.w;
 		dc.w = textw(tags[i]);
 		if(istile)
-			drawtext(tags[i], (i == tsel));
+			drawtext(tags[i], tsel[i]);
 		else
-			drawtext(tags[i], (i != tsel));
+			drawtext(tags[i], !tsel[i]);
 	}
 	x = dc.x + dc.w;
 	dc.w = textw(stext);

dwm.h

@@ -69,12 +69,12 @@ struct Client {
 
 extern const char *tags[];
 extern char stext[1024];
-extern int tsel, screen, sx, sy, sw, sh, bx, by, bw, bh, mw;
+extern int screen, sx, sy, sw, sh, bx, by, bw, bh, mw;
 extern unsigned int ntags;
 extern void (*handler[LASTEvent])(XEvent *);
 extern void (*arrange)(Arg *);
 extern Atom wmatom[WMLast], netatom[NetLast];
-extern Bool running, issel;
+extern Bool running, issel, *tsel;
 extern Client *clients, *sel;
 extern Cursor cursor[CurLast];
 extern DC dc;
@@ -121,6 +121,7 @@ extern void appendtag(Arg *arg);
 extern void dofloat(Arg *arg);
 extern void dotile(Arg *arg);
 extern void initrregs();
+extern Bool isvisible(Client *c);
 extern Client *getnext(Client *c);
 extern Client *getprev(Client *c);
 extern void replacetag(Arg *arg);

event.c

@@ -108,6 +108,12 @@ buttonpress(XEvent *e)
 			for(a.i = 0; a.i < ntags; a.i++) {
 				x += textw(tags[a.i]);
 				if(ev->x < x) {
+					if(ev->button == Button3) {
+						tsel[a.i] = True;
+						arrange(NULL);
+						drawall();
+					}
+					else
 						view(&a);
 					return;
 				}

main.c

@@ -83,7 +83,7 @@ xerrorstart(Display *dsply, XErrorEvent *ee)
 /* extern */
 
 char stext[1024];
-int tsel = DEFTAG;
+Bool *tsel;
 int screen, sx, sy, sw, sh, bx, by, bw, bh, mw;
 unsigned int ntags;
 Atom wmatom[WMLast], netatom[NetLast];
@@ -213,6 +213,8 @@ main(int argc, char *argv[])
 	initrregs();
 
 	for(ntags = 0; tags[ntags]; ntags++);
+	tsel = emallocz(sizeof(Bool) * ntags);
+	tsel[DEFTAG] = True;
 
 	/* style */
 	dc.bg = getcolor(BGCOLOR);

tag.c

@@ -51,7 +51,7 @@ dofloat(Arg *arg)
 
 	for(c = clients; c; c = c->next) {
 		c->ismax = False;
-		if(c->tags[tsel]) {
+		if(isvisible(c)) {
 			resize(c, True, TopLeft);
 		}
 		else
@@ -74,7 +74,7 @@ dotile(Arg *arg)
 
 	w = sw - mw;
 	for(n = 0, c = clients; c; c = c->next)
-		if(c->tags[tsel] && !c->isfloat)
+		if(isvisible(c) && !c->isfloat)
 			n++;
 
 	if(n > 1)
@@ -84,7 +84,7 @@ dotile(Arg *arg)
 
 	for(i = 0, c = clients; c; c = c->next) {
 		c->ismax = False;
-		if(c->tags[tsel]) {
+		if(isvisible(c)) {
 			if(c->isfloat) {
 				higher(c);
 				resize(c, True, TopLeft);
@@ -135,14 +135,14 @@ dotile(Arg *arg)
 Client *
 getnext(Client *c)
 {
-	for(; c && !c->tags[tsel]; c = c->next);
+	for(; c && !isvisible(c); c = c->next);
 	return c;
 }
 
 Client *
 getprev(Client *c)
 {
-	for(; c && !c->tags[tsel]; c = c->prev);
+	for(; c && !isvisible(c); c = c->prev);
 	return c;
 }
 
@@ -175,6 +175,17 @@ initrregs()
 	}
 }
 
+Bool
+isvisible(Client *c)
+{
+	unsigned int i;
+
+	for(i = 0; i < ntags; i++)
+		if(c->tags[i] && tsel[i])
+			return True;
+	return False;
+}
+
 void
 replacetag(Arg *arg)
 {
@@ -217,7 +228,8 @@ settags(Client *c)
 			XFree(ch.res_name);
 	}
 	if(!matched)
-		c->tags[tsel] = True;
+		for(i = 0; i < ntags; i++)
+			c->tags[i] = tsel[i];
 }
 
 void
@@ -230,7 +242,11 @@ togglemode(Arg *arg)
 void
 view(Arg *arg)
 {
-	tsel = arg->i;
+	unsigned int i;
+
+	for(i = 0; i < ntags; i++)
+		tsel[i] = False;
+	tsel[arg->i] = True;
 	arrange(NULL);
 	drawall();
 }
@@ -238,13 +254,19 @@ view(Arg *arg)
 void
 viewnext(Arg *arg)
 {
-	arg->i = (tsel < ntags-1) ? tsel+1 : 0;
+	unsigned int i;
+
+	for(i = 0; !tsel[i]; i++);
+	arg->i = (i < ntags-1) ? i+1 : 0;
 	view(arg);
 }
 
 void
 viewprev(Arg *arg)
 {
-	arg->i = (tsel > 0) ? tsel-1 : ntags-1;
+	unsigned int i;
+
+	for(i = 0; !tsel[i]; i++);
+	arg->i = (i > 0) ? i-1 : ntags-1;
 	view(arg);
 }