diff --git a/src/lib.rs b/src/lib.rs
index 12bf2095..af0706d3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,7 +58,6 @@ pub struct WindowBuilder {
     title: String,
     monitor: Option<winimpl::MonitorID>,
     gl_version: Option<(uint, uint)>,
-    is_fullscreen: bool,
 }
 
 impl WindowBuilder {
@@ -69,7 +68,6 @@ impl WindowBuilder {
             title: "gl-init-rs window".to_string(),
             monitor: None,
             gl_version: None,
-            is_fullscreen: false,
         }
     }
 
@@ -93,7 +91,6 @@ impl WindowBuilder {
     pub fn with_fullscreen(mut self, monitor: MonitorID) -> WindowBuilder {
         let MonitorID(monitor) = monitor;
         self.monitor = Some(monitor);
-        self.is_fullscreen = true;
         self
     }
 
diff --git a/src/x11/mod.rs b/src/x11/mod.rs
index 97552b0b..7d732a2a 100644
--- a/src/x11/mod.rs
+++ b/src/x11/mod.rs
@@ -129,7 +129,7 @@ impl Window {
         };
 
         let mut window_attributes = ffi::CWBorderPixel | ffi::CWColormap | ffi:: CWEventMask;
-        if builder.is_fullscreen {
+        if builder.monitor.is_some() {
             window_attributes |= ffi::CWOverrideRedirect;
             unsafe {
                 ffi::XF86VidModeSwitchToMode(display, screen_id, *modes.offset(best_mode as int));
@@ -251,7 +251,7 @@ impl Window {
             wm_delete_window: wm_delete_window,
             xf86_desk_mode: xf86_desk_mode,
             screen_id: screen_id,
-            is_fullscreen: builder.is_fullscreen,
+            is_fullscreen: builder.monitor.is_some(),
         };
 
         // calling glViewport