Currently, it is possible to input a '.' (Period) character into the name of a DataProperty, however, it will be rejected by the Data Panel as invalid, and revert back to the name it had prior to inputting this name with a period. This is the correct, and expected behaviour.

However, where an issue occurs, is that after attempting to submit a name with a period, clicking on the TextBox for the name will display the rejected name with the period.

Repro Steps:

1) Create a Studio Project featuring a MainPage.xaml

2) Navigate to the DataPanel, create a new Structure, then create a new Property for this Structure.
Observe how the new Property is named 'Property000'.

3) Double-click on 'Property000', input 'My.Property.Name', and press [Enter] to submit the name.
Observe how the name has reverted to 'Property000' (as expected).

4) Double-click on 'Property000' again.
Observe how the name shows the rejected name that was input in Step 3).

Expected Results: Editing the name of the Property, edits the last accepted name, and not the last name that was attempted to be input.
Expected Results: When an invalid character is attempted to be submitted in a field, a yellow 'Invalid name' warning toast appears, similar to when attempting to rename Element names to ones featuring invalid characters.