Repro Steps:
1) Create a new page, in a fresh project.
2) Navigate to the Data panel, and under ApplicationResources, select GlobalResources.xaml
3) With GlobalResources selected, under the Resource Creation panel, type 'Color' and add a new Color.
4) Edit the values of the Color in the right-side properties panel.

Observe how Color.001 does not appear in the list of resources.

5) Within the Resources panel, click on the 'Page' under the parentship of the created page.
6) Click back on 'GlobalResources.xaml'.

Observe how Color.001 now does appear in the list of resources as expected.

Expected Results: Newly-created Global Resources appear in the Resources list at creation.