I'm not sure, but I think this is a regression (it didn't use to be this way).

A button that is flagged as constructive and currently disabled has a green border around its otherwise grey button. When hovering the button the border becomes grey, so it doesn't seem intentional that the border is green (otherwise it should have a hover implementation as well).

This is most visible when opening VisualEditor, the save button has emits this behaviour.

Version: unspecified
Severity: normal