diff --git config.def.h config.def.h
index eaae8f3..bf48efb 100644
--- config.def.h
+++ config.def.h
@@ -26,9 +26,9 @@ static const Rule rules[] = {
 	 *	WM_CLASS(STRING) = instance, class
 	 *	WM_NAME(STRING) = title
 	 */
-	/* class      instance    title       tags mask     isfloating   monitor */
-	{ "Gimp",     NULL,       NULL,       0,            True,        -1 },
-	{ "Firefox",  NULL,       NULL,       1 << 8,       False,       -1 },
+	/* class      instance    title       tags mask     isfloating  ispermanent  monitor */
+	{ "Gimp",     NULL,       NULL,       0,            True,       False,       -1 },
+	{ "Firefox",  NULL,       NULL,       1 << 8,       False,      False,       -1 },
 };
 
 /* layout(s) */
diff --git dwm.c dwm.c
index 169adcb..f0c7589 100644
--- dwm.c
+++ dwm.c
@@ -92,7 +92,7 @@ struct Client {
 	int basew, baseh, incw, inch, maxw, maxh, minw, minh;
 	int bw, oldbw;
 	unsigned int tags;
-	Bool isfixed, isfloating, isurgent, neverfocus, oldstate, isfullscreen;
+	Bool isfixed, ispermanent, isfloating, isurgent, neverfocus, oldstate, isfullscreen;
 	Client *next;
 	Client *snext;
 	Monitor *mon;
@@ -138,6 +138,7 @@ typedef struct {
 	const char *title;
 	unsigned int tags;
 	Bool isfloating;
+	Bool ispermanent;
 	int monitor;
 } Rule;
 
@@ -295,6 +296,7 @@ applyrules(Client *c) {
 		&& (!r->instance || strstr(instance, r->instance)))
 		{
 			c->isfloating = r->isfloating;
+			c->ispermanent = r->ispermanent;
 			c->tags |= r->tags;
 			for(m = mons; m && m->num != r->monitor; m = m->next);
 			if(m)
@@ -989,7 +991,7 @@ keypress(XEvent *e) {
 
 void
 killclient(const Arg *arg) {
-	if(!selmon->sel)
+	if(!selmon->sel || selmon->sel->ispermanent)
 		return;
 	if(!sendevent(selmon->sel, wmatom[WMDelete])) {
 		XGrabServer(dpy);