Currently, if you have a Storyboard "Storyboard_A", then rename it to "Storyboard_B", if you rename it back to "Storyboard_A", it will produce a warning stating "A storyboard with the name "Storyboard_A" already exists.
This results in making it impossible to rename the Storyboard back to "Storyboard_A".

Repro Steps:

1) Download and open the attached Studio Project.

2) In the Navigator, identify the UserControl named "TopographicPattern_UserControl" (found under the "Foreground_Group_Grid" Grid under the RootGrid.

3) Enter the TopographicPattern_UserControl's context menu, and open the UserControl's Template for Edit
This will then open in the dummy Template Editor.

4) Within the UserControl Template, navigate to the Animation/Storyboards Panel.
Inside, you will find a Storyboard named "TopoPatternn_Animation" (note how there is an extra 'n' in the word 'Paternn')

5) Rename the Storyboard to "TopoPattern_Animation" with the proper spelling of "Pattern".

6) Rename the Storyboard back to "TopoPatternn_Animation" with the incorrect spelling of "Patternn".

Observe how although there is no Storyboard named "TopoPatternn_Animation", that a toast appears stating that the name is already existing.

Expected Results: Names that no longer exist used as not cached and misidentified as being in-use.