Currently, ListBox Items, even when a contained TextBlock is set to 'Wrap', does not wrap within its allocated space, and instead overflows, causing its container to grow with the space taken by the text.

This is due to a couple issues:

1) By Default, the TextBlock inside of the ListBoxItem Template, is set to 'NoWrap'.

2) The ListBox Template is made up of a ScrollViewer, that has a HorizontalScroll set to 'Auto', which causes the Item to take as much space as it needs, instead of being constrained to the size allocated to it.

3) The ListBox Scrollviewer has a Scrollbar which does not appear until the scene is being 'Played', and there is enough content taken up that an overflow is caused. This makes it difficult to diagnose issues in Edit Mode.

This Ticket centers around:
Making the ListBox Scrollviewer's visible by default the moment there is content that overflows the space given to it.
If possible, perhaps setting the TextBlock to 'Wrap' just as we do with TextBlock's dragged from the Add Element Panel may be beneficial.

Repro Steps:

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

2) Introduce a ListBox Element to the Page.
This will have default values by default.

3) Create a Template for the ListBoxItemsPanel, and modify it into a 4 Col, 2 Row Uniform Grid.

4) Create a Template for the ListBoxItem, and expand its text size until the default values no longer fit within the size of the UniformGrid cell, then set the TextBlock to 'Wrap'.

Observe how the TextBlock is not succesfully wrapping at the edge of the UniformGrid cell.

Observe how there is no indication that content is overflowing the Page bounds.

5) Return back to the Page, click on the ListBox, identify the HorizontalScrollBar Property, and set it to 'Disabled'.

Observe the text now wrapping successfully.

Expected Results: The mechanics of the ListBox Element are apparent to users whilst developing ListBoxes.