Flickering, disappearing screen & sprites in editor

[triggly_glix]

As the subject says sprites are disappearing in the editor when I click play - or at various moments in the interaction. If I pause the editor and then resume playing they come back...
attaching a link to a video to show the problem clearly - (this is happening a lot and is quite affecting my workflow)
any help very much appreciated...

https://dl.dropboxusercontent.com/u/11634924/Unity_NGui_Flickering.mp4

[ArenMook]

Use NGUI 2.7.0 with "depth sorting" turned on on your panels.

[triggly_glix]

Hi Aren,
thanks for responding on this - so I've now updated to NGUI 2.7.0 and I've turned on depth sorting but I'm still seeing similar problems. I could post another video but basically it's the same - things don't appear and then i pause and unpause the app and they are there. For example a popup doesn't reach it's full scale - i pause and unpause and ah, there it is. Or i transition from one menu to another the screen stays black - when i pause and unpause the editor i see that in fact the screen is there...
any more clues please ?
thanks

[ArenMook]

I just had a second look at your video and it's not what I thought. I don't even know what's going on there. It's like as if Unity is only drawing to a part of the screen. Are you doing something funky there with stencils or the depth buffer? Are you clearing the depth buffer correctly?