Can't set alias for structure ("Aliases" option doesn't work)

[mattl91]

When I attempt to specify an alias for a structure, I get a "Failed to set text" error.

To Reproduce
Steps to reproduce the behavior:

1. Open the Harmony Core GUI tool and go to the Structures screen.
2. Select (highlight) a structure in the upper pane of the Structures screen.
3. In the lower pane of the Structures screen, double-click the Aliases option.
4. In the "Enter new value" dialog, enter an alias name and click OK. A "Failed to set text" message box will open with the following text:
   Object of type 'System.String' cannot be converted to type 'System.Collections.Generic.List[System.String]'.

GUI tool version: 6.0.249