I'd like to create the effect of an ember glowing, as if someone blew on it. I can create the end image with a radial gradient of orange and red, and I can make the beginning image black, but I'm having trouble tweening between the two. The tween complains: Motion tweening will not occur on layers with ungrouped shapes or on layers with more than one group or symbol." If I use a solid color as the beginning and end points the tween works ok. I can also tween the alpha of a gradient, but the effect isn't really what I'm looking for. Is there an easy way to create this "glowing ember" effect.