diff --git a/ChangeLog b/ChangeLog
index 62bb1159c..ab65f0b76 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2012-10-08  Doug Simons <doug.simons@testplant.com>
+
+        * NSWindow.m: Center on the main screen if window is off screen.
+
 2012-09-04  Jonathan Gillaspie <jonathan.gillaspie@testplant.com>
 
 	* Source/NSWorkspace.m: Log if we have a distributed lock error instead of raise fatally.
diff --git a/Source/NSWindow.m b/Source/NSWindow.m
index c43ceda52..2f625c65b 100644
--- a/Source/NSWindow.m
+++ b/Source/NSWindow.m
@@ -2067,7 +2067,12 @@ many times.
 
 - (void) center
 {
-  NSSize screenSize = [[self screen] visibleFrame].size;
+  NSScreen *screen = [self screen];
+  // if not visible on any screen, center on the main screen
+  if (!screen) {
+	screen = [NSScreen mainScreen];
+  }
+  NSSize screenSize = [screen visibleFrame].size;
   NSPoint origin = _frame.origin;
 
   origin.x = (screenSize.width - _frame.size.width) / 2;