diff --git a/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.cxx b/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.cxx
index ea26c4d47..f77fc9e04 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.cxx
+++ b/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.cxx
@@ -317,6 +317,7 @@ void Fl_Cocoa_Window_Driver::capture_titlebar_and_borders(Fl_RGB_Image*& top, Fl
   left = bottom = right = NULL;
   int htop, hleft, hright, hbottom;
   Fl_Cocoa_Window_Driver::decoration_sizes(&htop, &hleft,  &hright, &hbottom);
+  if (htop == 0) return; // when window is fullscreen
   CALayer *layer = get_titlebar_layer();
   CGColorSpaceRef cspace = CGColorSpaceCreateDeviceRGB();
   float s = Fl::screen_driver()->scale(screen_num());