Standard example: Texture in SGNode - Rendering FBOs

[qthree]

Take two stock examples and replace logo renderer (one cpp for 2 examples) to this dummy:
http://pastebin.com/peYzuwss

Multi-threads version works well - draws green rectangle
Single thread blink green for 1 frame and than shows only red background.

1. Why?
2. What must i do to get same results in both situations?

(ubuntu x64 5.1.0)

sry4engrish

[qthree]

3. Also, multi-threads version doesn't work in win7 (x64, opengl).
   @ARB::createContext: wglCreateContextAttribsARB() failed (GL error code: 0x502@
   because of sharing with other context
   @m_context->setShareContext(context);@

upd: already found about it https://bugreports.qt-project.org/browse/QTBUG-30077
but 1 and 2 still important for me.

[sletta]

Both examples work fine for me with ubuntu 13.04, 64-bit. What is your video driver?

[qthree]

On ubuntu examples works well without modifications, but without shader programm one-thread example does not work.
So, i use gDEBugger GL and found that after after qml drawing depth test enabled and some shader programm binded. So this helps me:
@
QOpenGLFunctions_2_1 glf21;
glf21.initializeOpenGLFunctions();
.....
glDisable(GL_DEPTH_TEST);
glf21.glUseProgram(0);@