Currently, if you have an Element used in a Timeline (VisualState or Storyboard), and the Element is deleted from the Navigator or Stage, a 'Template Root' line item is created in its place in the Timeline where it used to be prior to deletion.

See attached video.

Repro Steps:

1) Download, unzip, and open the attached Studio Project.

2) On the MainPage, right-click on the ContentControl on the right of the screen (Squad listing), and from its context menu select 'Templates' --> 'Content' --> 'Edit'.

3) Within the ContentControl Content Template just opened, right-click on the ListBox containing each player, and from its Context Menu, navigate to 'Templates' --> 'ItemContainer' --> 'Edit'.

4) Within the ItemContainer Template, identify the CheckBox Element on the right of each player row, right-click on it, and from its Context Menu navigate to 'Templates' --> 'CheckBox' --> 'Edit'.

5) Within the CheckBox Template, navigate to the Animations/VisualStates Panel, and select the 'Checked' Visual State.
This will reveal the VisualState's Timeline.

6) In the Timeline, select the Element named 'Icon_Cross_Path'. (This will also select it in the Navigator and set us up for the next step)

8) Right-click on ''Icon_Cross_Path' in the Navigator, and from the 'Edit' section of the Context Menu, select 'Delete'.

Observe how whilst the deletion of 'Icon_Cross_Path' was successfully removed from the Navigator and the Timeline. on the other hand a 'Template Root' Element has been added to the Timeline containing the Keyframe that used to belong to 'Icon_Cross_Path'.

9) Navigate to the "MouseOver" Visual State.
Observe how a similar behaviour has also occurred there too.

Expected Results: Deleting an Element from the Navigator also removes any associated entries across any Timelines.