Beta 4 OS X: Effect and Sprite Weirdness

Has anyone else had an issue with particle effect thumbnails not showing in the Level Editor? WhenI try to place a particle effect in the Level Editor it is created in the scene where I clicked but it does not run. I can edit properties but nothing happens. The same thing happens with some static sprites: I select them in the Create tab and place them in the Level Editor but they don't show up, or if they do, they show as the last static sprite that worked. The scroller counter-parts work fine though.

- Matt VG