1) What happened
Context loss causes loss to materials, textures and shaders.

2) How can we reproduce it using the example you attached
1. Open the supplied project
2. Open the ContextLossExample-scene
3. Build targeting the Flash Player.
4. Once the game is running, press CTRL ALT DELETE (Windows)
5. Return to the game.
6. Notice the loss of materials.

Expected result:
The scene should look the same before and after.

Actual result:
The materials fail to render properly, turning them black.

This happens in Firefox and Chrome (not tested in IE). Tested on Flash Player 11.5.5. Built using Unity 4.0.0f7 (not beta).