Whenever you modify a layer in the transition or behavior designer by moving it, hiding it, connecting it, pulling it out or otherwise changing its properties, an animation tag is created. You'll see a white tag replace the layer's name. These tags are what allows transitions to be reused. When you reuse a transition or behavior, then edit it, you will be able to assign tags to specific layers, giving Flinto the information it needs to use that transition or behavior on that screen or group.