Missing rendering in Unity dash

Submitted by Christopher James Halse Rogers

Assigned to Marek Olšák @mareko

Link to original bug (#36332)

Description

Forwarded from https://bugs.launchpad.net/ubuntu/+source/unity/+bug/726033

When rendering the Unity dash icons are frequently missing from the rendering. This video is a good demonstration of the problem: https://launchpadlibrarian.net/68813544/unity-bug.ogv

This works on r600g, nouveau, i915 and i965, so it looks like it's a bug somewhere in r300g.

The dash rendering uses FBOs and ARB shaders, with glscissor for clipping.

Version: git