At the moment we ask the user to enter the name of the ODBC data source in a text field. Ideally we'd show a combo box with all configured data sources on Windows so the user can simply select one of the available sources.

To get the list of configured sources, see:

https://docs.microsoft.com/en-us/sql/odbc/reference/syntax/sqldatasources-function?view=sql-server-2017
https://stackoverflow.com/questions/33021280/getting-list-of-available-odbc-data-sources-in-my-qt-application