Currently, there is an issue where if you create a Resource in an custom Dictionary merged into GlobalResources.xaml, and you attempt to use it inside of a Template, it will not be available to select until all Documents are closed and re-opened.

See attached video.

Repro Steps:

1) Create a new Studio Project featuring a MainPage.xaml

2) Create a new ResourceDictionary, and merged it into GlobalResources.xaml

3) Create a new Template for the first Button on the Page, stored in GlobalResources.xaml
This will open the Button Template in the Button Inline Template Editor.

4) In the Template, replace the default ContentPresenter with a TextBlock, give it a custom FontSize, then save the FontSize as a Resource to the Dictionary created in Step 2).

5) Exit the Template of the first Button, then save and close all open Documents.

6) Re-open MainPage.xaml, then from the Resources Panel, duplicate the FontSize Resource created in Step 4), and give it a custom name.

7) Create a Template for the second Button Element on the Stage.
This will open the Button Template in the Button Inline Template Editor.

8) As in Step 4, replace the Default ContentPresenter with a TextBlock.

9) Select the TextBlock introduced in Step 8), hover over its FontSize Property, click on its 3-Dot menu, and from this context menu, select 'Apply Resource'.

Observe how only the first FontSize that was created in Step 4) prior to saving, closing, and re-opening all documents is available to pick from in the Resources.

10) Save all documents, close all open tabs, and re-open MainPage.xaml, then re-enter the second ButtonTemplate, select the TextBlock, and apply a Resource to its FontSize Property.

Observe how now both Resources are available to pick from.

Expected Results: Created Resources are immediately to use after being created.