User opens existing NGFP or creates a form from Shp (i.e. the data is already imported)
User clicks "Update data", dialog for selecting OGR source appears and user selects data source
Data structure from the data source and from NGFP are compared.
4a. If data structures are identical, new data overwrites existing.
4b. If data structures differ, error message appears and nothing happens.
New tool for Tools tab - "Update data".
Scenario of use: