diff --git a/src/Monitor.vala b/src/Monitor.vala
index e0f722c..0b74d7c 100644
--- a/src/Monitor.vala
+++ b/src/Monitor.vala
@@ -29,8 +29,8 @@ class Monitor {
 	public signal void connected(string name);
 	public signal void disconnected(string name);
 
-	public Monitor(Gdk.Screen scr) {
-		screen = scr;
+	public Monitor(Gdk.Screen? scr = null) {
+		screen = (screen != null) ? scr : Gdk.Screen.get_default();
 		monitors = get_list();
 		screen.monitors_changed.connect(on_monitor_changed);
 	}