pixelmask don't work inside a feathers list with cliprect

[Seb-AS]

http://forum.starling-framework.org/topic/cliprects-and-pixelmasks?replies=1#post-72423

1. say you have 5 tiles across, centered in the middle of your screen. Each one has 1 pixelMask. Say there's enough from for another tile on each side if you wanted. The List is configured to load 2 pages, and culling is on -- so on load, it loads the 5 tiles you see, and 5 you don't see.

2. on load, and when you scroll, the tiles that are on the next page flickers. After the flickering, everything looks correct.

Seems like when we apply the pixel mask, the cliprect of the list is turned off or disabled for a split second.