In editor advanced section, images are not showing to select thumbnail of the post. So post creation not allowing thumbnail selection, it was working before, perhaps some new changes, removed or broke it. Find out and improve logic.
@igormuba next time, in PR description or commits messages, add Fixes #1147 message referencing this issue number. Once PR merged, it should automatically close this issue as well with it.
In editor advanced section, images are not showing to select thumbnail of the post. So post creation not allowing thumbnail selection, it was working before, perhaps some new changes, removed or broke it. Find out and improve logic.