Fixed glfwDestroyWindow not flushing the output buffer.

README.md

@@ -72,6 +72,7 @@ The following dependencies are needed by the examples and test programs:
  - [X11] Bugfix: No check was made for the presence GLX 1.3 when
                  `GLX_SGIX_fbconfig` was unavailable
  - [X11] Bugfix: The message type of ICCCM protocol events was not checked
+ - [X11] Bugfix: `glfwDestroyWindow` did not flush the output buffer.
 
 
 ## Contact

src/x11_window.c

@@ -1106,6 +1106,8 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
         XFreeColormap(_glfw.x11.display, window->x11.colormap);
         window->x11.colormap = (Colormap) 0;
     }
+
+    XFlush(_glfw.x11.display);
 }
 
 void _glfwPlatformSetWindowTitle(_GLFWwindow* window, const char* title)