STR: * Enable display list retaining. * Visit https://cs.chromium.org/ Expected: * See the chromium codesearch page. Actual: * See it, then see how the whole tab becomes white, and doesn't come back until you switch to another tab and back (forcing a full repaint, presumably).

I can reproduce this with mozilla-central, but it's fixed on the graphics branch. Haven't bisected to know exactly which patch fixed it, but it should be uplifted today or tomorrow.

This works nicely now in the latest nightly :)