diff -Naur old/config.def.h new/config.def.h
--- old/config.def.h	2015-12-13 23:25:31.809649303 +0000
+++ new/config.def.h	2015-12-13 23:10:04.011248379 +0000
@@ -11,6 +11,8 @@
 static const char selbordercolor[]  = "#005577";
 static const char selbgcolor[]      = "#005577";
 static const char selfgcolor[]      = "#eeeeee";
+static const char normmarkcolor[]   = "#ff0000";
+static const char selmarkcolor[]    = "#ff00ff";
 static const unsigned int borderpx  = 1;        /* border pixel of windows */
 static const unsigned int snap      = 32;       /* snap pixel */
 static const int showbar            = 1;        /* 0 means no bar */
@@ -68,7 +70,8 @@
 	{ MODKEY,                       XK_d,      incnmaster,     {.i = -1 } },
 	{ MODKEY,                       XK_h,      setmfact,       {.f = -0.05} },
 	{ MODKEY,                       XK_l,      setmfact,       {.f = +0.05} },
-	{ MODKEY,                       XK_Return, zoom,           {0} },
+	{ MODKEY,                       XK_Return, swap,           {0} },
+	{ MODKEY,                       XK_semicolon, setmark,     {.i = 1} },
 	{ MODKEY,                       XK_Tab,    view,           {0} },
 	{ MODKEY|ShiftMask,             XK_c,      killclient,     {0} },
 	{ MODKEY,                       XK_t,      setlayout,      {.v = &layouts[0]} },
diff -Naur old/drw.h new/drw.h
--- old/drw.h	2015-11-08 22:39:37.000000000 +0000
+++ new/drw.h	2015-12-13 22:59:53.387882222 +0000
@@ -23,6 +23,7 @@
 	Clr *fg;
 	Clr *bg;
 	Clr *border;
+	Clr *mark;
 } ClrScheme;
 
 typedef struct {
diff -Naur old/dwm.c new/dwm.c
--- old/dwm.c	2015-11-08 22:39:37.000000000 +0000
+++ new/dwm.c	2015-12-13 23:21:13.226882033 +0000
@@ -93,6 +93,7 @@
 	int bw, oldbw;
 	unsigned int tags;
 	int isfixed, isfloating, isurgent, neverfocus, oldstate, isfullscreen;
+	int ismarked;
 	Client *next;
 	Client *snext;
 	Monitor *mon;
@@ -127,6 +128,7 @@
 	Client *clients;
 	Client *sel;
 	Client *stack;
+	Client *mark;
 	Monitor *next;
 	Window barwin;
 	const Layout *lt[2];
@@ -201,11 +203,13 @@
 static void setfocus(Client *c);
 static void setfullscreen(Client *c, int fullscreen);
 static void setlayout(const Arg *arg);
+static void setmark(const Arg *arg);
 static void setmfact(const Arg *arg);
 static void setup(void);
 static void showhide(Client *c);
 static void sigchld(int unused);
 static void spawn(const Arg *arg);
+static void swap(const Arg *arg);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
 static void tile(Monitor *);
@@ -485,6 +489,7 @@
 		drw_clr_free(scheme[i].border);
 		drw_clr_free(scheme[i].bg);
 		drw_clr_free(scheme[i].fg);
+		drw_clr_free(scheme[i].mark);
 	}
 	drw_free(drw);
 	XSync(dpy, False);
@@ -807,7 +812,10 @@
 		detachstack(c);
 		attachstack(c);
 		grabbuttons(c, 1);
-		XSetWindowBorder(dpy, c->win, scheme[SchemeSel].border->pix);
+		if (c->ismarked)
+			XSetWindowBorder(dpy, c->win, scheme[SchemeSel].mark->pix);
+		else
+			XSetWindowBorder(dpy, c->win, scheme[SchemeSel].border->pix);
 		setfocus(c);
 	} else {
 		XSetInputFocus(dpy, root, RevertToPointerRoot, CurrentTime);
@@ -1018,6 +1026,10 @@
 {
 	if (!selmon->sel)
 		return;
+	if (selmon->mark == selmon->sel) {
+		selmon->mark->ismarked = 0;
+		selmon->mark = 0;
+	}
 	if (!sendevent(selmon->sel, wmatom[WMDelete])) {
 		XGrabServer(dpy);
 		XSetErrorHandler(xerrordummy);
@@ -1065,7 +1077,10 @@
 
 	wc.border_width = c->bw;
 	XConfigureWindow(dpy, w, CWBorderWidth, &wc);
-	XSetWindowBorder(dpy, w, scheme[SchemeNorm].border->pix);
+	if (c->ismarked)
+		XSetWindowBorder(dpy, w, scheme[SchemeNorm].mark->pix);
+	else
+		XSetWindowBorder(dpy, w, scheme[SchemeNorm].border->pix);
 	configure(c); /* propagates border_width, if size doesn't change */
 	updatewindowtype(c);
 	updatesizehints(c);
@@ -1528,6 +1543,29 @@
 		drawbar(selmon);
 }
 
+void
+setmark(const Arg *arg)
+{
+	if (!selmon->sel)
+		return;
+	if (selmon->sel == selmon->mark) {
+		selmon->mark->ismarked = 0;
+		XSetWindowBorder(dpy, selmon->mark->win, scheme[SchemeSel].border->pix);
+		selmon->mark = 0;
+	} else {
+		if (selmon->mark) {
+			selmon->mark->ismarked = 0;
+			XSetWindowBorder(dpy, selmon->mark->win, scheme[SchemeNorm].border->pix);
+			selmon->mark = 0;
+		}
+		if (arg && arg->i) {
+			selmon->sel->ismarked = 1;
+			XSetWindowBorder(dpy, selmon->sel->win, scheme[SchemeSel].mark->pix);
+			selmon->mark = selmon->sel;
+		}
+	}
+}
+
 /* arg > 1.0 will set mfact absolutly */
 void
 setmfact(const Arg *arg)
@@ -1583,9 +1621,11 @@
 	scheme[SchemeNorm].border = drw_clr_create(drw, normbordercolor);
 	scheme[SchemeNorm].bg = drw_clr_create(drw, normbgcolor);
 	scheme[SchemeNorm].fg = drw_clr_create(drw, normfgcolor);
+	scheme[SchemeNorm].mark = drw_clr_create(drw, normmarkcolor);
 	scheme[SchemeSel].border = drw_clr_create(drw, selbordercolor);
 	scheme[SchemeSel].bg = drw_clr_create(drw, selbgcolor);
 	scheme[SchemeSel].fg = drw_clr_create(drw, selfgcolor);
+	scheme[SchemeSel].mark = drw_clr_create(drw, selmarkcolor);
 	/* init bars */
 	updatebars();
 	updatestatus();
@@ -1646,6 +1686,36 @@
 }
 
 void
+swap(const Arg *arg)
+{
+	Client **ts, **tm, *c;
+
+	if (!selmon->mark) {
+		zoom(0);
+		return;
+	}
+
+	if (!selmon->sel || selmon->mark == selmon->sel)
+		return;
+	if (!selmon->lt[selmon->sellt]->arrange || (selmon->sel->isfloating))
+		return;
+
+	for (ts = &selmon->clients; *ts != selmon->sel; ts = &(*ts)->next);
+	for (tm = &selmon->clients; *tm != selmon->mark; tm = &(*tm)->next);
+
+	c = *ts;
+	*ts = *tm;
+	*tm = c;
+
+	c = selmon->sel->next;
+	selmon->sel->next = selmon->mark->next;
+	selmon->mark->next = c;
+
+	setmark(0);
+	arrange(selmon);
+}
+
+void
 tag(const Arg *arg)
 {
 	if (selmon->sel && arg->ui & TAGMASK) {
@@ -1745,7 +1815,10 @@
 	if (!c)
 		return;
 	grabbuttons(c, 0);
-	XSetWindowBorder(dpy, c->win, scheme[SchemeNorm].border->pix);
+	if (c->ismarked)
+		XSetWindowBorder(dpy, c->win, scheme[SchemeNorm].mark->pix);
+	else
+		XSetWindowBorder(dpy, c->win, scheme[SchemeNorm].border->pix);
 	if (setfocus) {
 		XSetInputFocus(dpy, root, RevertToPointerRoot, CurrentTime);
 		XDeleteProperty(dpy, root, netatom[NetActiveWindow]);