After copying a keyframe (via context menu or Ctrl+C), pasting it does not work.

REPRO STEPS

1. Start from a blank project.
2. Create a new Panel.
3. Add any element (in the video, a Button).
4. Create a ControlTemplate from that element.
5. Open Animation - Visual States.
6. Select any state (in the video, Normal).
7. In the Navigator, select the ContentPresenter.
8. Change any property (in the video, Opacity).
9. In the Timeline, open the context menu on the Opacity keyframe and select Copy.
10. Move the playhead a few seconds ahead.
11. Paste using Ctrl+V.
12. Observe that the timeline hierarchy collapses and no keyframe is pasted.

Expected Result
Pasting a keyframe should paste a new keyframe at the current playhead position, without collapsing anything in the timeline hierarchy.

Actual Result
The timeline hierarchy collapses and no keyframe is pasted.