Thank you for the new version 1.5.0–well done! What I appreciate most, is “start in Background / at system start”. Below these entries there is enough space to add “start windows explorer automatically”–if you would be so kind 
Unfortunately, I get an error message from Windows when I try to open an Explorer Window in Autostart; apparently the vault is not yet ready at the time.
Thanks for the suggestion! We have a feature-request on our issue tracker to rework the unlock vault workflow and one of the ideas is also your proposal. Stay tuned, it is planned to implement the feature request in one of its forms soon!
Short update: Since 1.5.4 the feature is implemented 