Currently, when populating any 'Source' Property field, Studio expects users to manually type in a syntax along the lines of:
studio:///TriggersExploration;component/MyPage.xaml

There is however no indication in the Studio UI that of the many syntaxes that the field could be populated with, that this is the expected one.

Ideally, instead of/in addition to raw manually-input text, these should offer a ComboBox/Dropdown of all compatible files that could be selected for this Property, akin to how Bitmap selection works in the context of Image Brush Properties

There are a few Elements that contain a 'Source' Property, but the easiest to access is the Component Element.

Repro Steps:

1) Create a Studio Project containing a MainPage.xaml

2) Create a Component from the Assets Panel.

3) Navigate to the Add Element Panel, identify the 'Component' Element, and drag-and-drop it to the root Grid, then select it to display its Properties Panel.

Pretending you don't know the expected syntax, attempt to display the Component created in Step 2) as the content of the Component introduced in Step 3).

Observe how there is no method to know the expected syntax to get the Component to appear.

Expected Results: A 'Source' value can easily be populated by the user without external help to determine what the expected syntax needs to be.