Currently, when setting a Style to be 'BasedOn' another, when making the selection of the base Style in the dropdown, it reverts back to the Default Style rather than the one chosen to be BasedOn.

Repro Steps:

1) Download and open the attached Project, and open the MainPage.xaml.
2) Right-Click on the YELLOW tile on the Stage, and from its ContextMenu, select 'Style', then 'Edit'. This will open the 'Derivative' Styled for Edit.

3) In the Style Dummy Editor, select the STYLE from the Navigator, and from the top of the Properties Panel, set its 'BasedOn' Property to be BasedOn the Style named 'CheckBox_Style_Base'.

Observe how upon making the selection, the value "CheckBox_Style_Base" isn't displayed in the collapsed Dropdown menu, and instead displays "[CheckBox default]". As a result, it is unclear as to whether the Style selected to be 'BasedOn' was correctly applied to this Style.

Expected Results: Selecting a Style from a Dropdown menu populates it in its collapsed state.