Fixed a crash in the boxes demo when using -graphicssystem opengl.

Several problems:
1. The demo leaked the scene contents, which caused cleanup problems.
2. The QGLContext::currentContext() could be changed behind Qt's back
   under Windows (the temp contexts never reset the current context).
3. QGLFormat::openGLVersionFlags() function would return uninitialized
   flags if the QGLWidget constructor happened to call
   qt_gl_preferGL2Engine().

Reviewed-by: Kim

1 files changed, 1 insertions, 1 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 97a4a73..0ad6772 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -1245,11 +1245,11 @@ QGLFormat::OpenGLVersionFlags QGLFormat::openGLVersionFlags()
         if (cachedDefault) {
             return defaultVersionFlags;
         } else {
-            cachedDefault = true;
             if (!hasOpenGL())
                 return defaultVersionFlags;
             dummy = new QGLWidget;
             dummy->makeCurrent(); // glGetString() needs a current context
+            cachedDefault = true;
         }
     }