Currently, we offer the ability to copy-paste keyframes of a Storyboard, Visual State, and Visual State Transition.

However, these keyframes can not be copied/pasted between different Timelines, even within the same Template which contain the same Elements.

To be determined if/how we may support copy-pasting Keyframes between different Pages/Templates which may not have all of the same Elements as featured in the Keyframes.
We likely have a couple options:
a) Don't allow cross Page/Template Keyframe copy-pasting.
b) Only Paste keyframes that have the same Elements detected in the new scope.

Repro Steps:

1) Create a Studio Project featuring a MainPage.xaml

2) Introduce a Button Element to the root Grid, and create a new Template for it, with any name, and stored in any location.
This will open the Button Template in the Inline Dummy Template Editor.

3) Navigate to the Animation Panel, and in the Visual States Tab, create any animation in the MouseOver Visual State.

4) Select the Keyframes created in Step 3), and simply paste them further along in the same timeline.
Observe how the copy-paste action functions as expected.

5) Select any other Visual State, and copy-paste any Keyframes from Step 3) into its Timeline.
Observe how the keyframes can't be copy-pasted between different timelines.

6) Repeat Steps 3) to 5) in different Visual State Transitions, or different Storyboards if desired (Optional)

Expected Results: Keyframes can be copy-pasted between different compatible timelines.