Fix the bug where drops from the main parts list could blow up.
Merge branch 'master' of github.com:robinhellen/vldraw
use the property rather than the old field.
make this a construct block rather than a constructor.
Switch to construct properties instead of fields.
Refactor to make it easier to switch to IIndex
Inject the dropped objec tlocators by DI
Refactor: Mof drag and drop code to its own namespace
Use a module to register all the drag and drop code