Freshly created encrypted wallets do have the "Create new receiving address" Button disabled. Closing and reopening fixes the issue.
<img width="803" alt="Bildschirmfoto 2020-10-23 um 12 52 48" src="https://user-images.githubusercontent.com/178464/96995762-fd764e80-152e-11eb-8c3a-001cbd3b1e4a.png">
Added 0.21.0 milestone.