Data should not be lost after form is sent and request failed on server side

For some actions, it is possible to lose data entered into form / wizard. This generally occurs whenever there is a failure on server side after sending a form containing invalid data (due to missing client-side validation or no possibility to validate users input).

An example of such action would be a creation of new datasource with existing name. Regardless the error, "New Datasource" wizard is closed after clicking on "Done" button in the last step and everything is lost.

Action as "closing wizard" or switching form back to view mode should happen only after receiving server response with no errors.