From 69e10b88b0a62542fe2324290637d76c565382f9 Mon Sep 17 00:00:00 2001
From: Camilla Berglund <elmindreda@elmindreda.org>
Date: Tue, 11 Feb 2014 15:46:54 +0100
Subject: [PATCH] Fixed uncaught BadWindow in EWMH check.

Fixes #234.
---
 README.md      | 2 ++
 src/x11_init.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/README.md b/README.md
index 1056e140..80bc5c8d 100644
--- a/README.md
+++ b/README.md
@@ -59,6 +59,8 @@ The following dependencies are needed by the examples and test programs:
  - [X11] Bugfix: The case of finding no usable CRTCs was not detected
  - [X11] Bugfix: Detection of broken Nvidia RandR gamma support did not verify
                  that at least one CRTC was present
+ - [X11] Bugfix: A stale `_NET_SUPPORTING_WM_CHECK` root window property would
+                 cause an uncaught `BadWindow` error
 
 
 ## Contact
diff --git a/src/x11_init.c b/src/x11_init.c
index 1f029791..84ecbf52 100644
--- a/src/x11_init.c
+++ b/src/x11_init.c
@@ -359,6 +359,8 @@ static void detectEWMH(void)
         return;
     }
 
+    _glfwGrabXErrorHandler();
+
     // It should be the ID of a child window (of the root)
     // Then we look for the same property on the child window
     if (_glfwGetWindowProperty(*windowFromRoot,
@@ -371,6 +373,10 @@ static void detectEWMH(void)
         return;
     }
 
+    _glfwReleaseXErrorHandler();
+    if (_glfw.x11.errorCode != Success)
+        return;
+
     // It should be the ID of that same child window
     if (*windowFromRoot != *windowFromChild)
     {