Prevent idle when fullscreen

config.h

@@ -1,5 +1,6 @@
 #include <X11/XF86keysym.h>
 /* appearance */
+static const int noidlefullscreen          = 1;  /* disable idle when fullscreen */
 static const int sloppyfocus               = 1;  /* focus follows mouse */
 static const int mousefollowsfocus         = 1;  /* mouse follows focus */
 static const int bypass_surface_visibility = 0;  /* 1 means idle inhibitors will disable idle tracking even if it's surface isn't visible  */

dwl.c

@@ -1890,8 +1890,11 @@ void
 killclient(const Arg *arg)
 {
 	Client *sel = focustop(selmon);
-	if (sel)
+	if (sel) {
 		client_send_close(sel);
+		if (noidlefullscreen)
+			checkidleinhibitor(NULL);
+	}
 }
 
 void
@@ -2444,10 +2447,16 @@ setfullscreen(Client *c, int fullscreen)
 	if (fullscreen) {
 		c->prev = c->geom;
 		resize(c, c->mon->m, 0);
+		if (noidlefullscreen) {
+			wlr_idle_set_enabled(idle, NULL, 0);
+			wlr_idle_notifier_v1_set_inhibited(idle_notifier, 1);
+		}
 	} else {
 		/* restore previous size instead of arrange for floating windows since
 		 * client positions are set by the user and cannot be recalculated */
 		resize(c, c->prev, 0);
+		if (noidlefullscreen)
+			checkidleinhibitor(NULL);
 	}
 	arrange(c->mon);
 	printstatus();