On macOS, selecting the Hide Defold option from the Defold menu, or pressing shortcut Command-H does not hide the application. Instead, it brings up an About Defold dialogue. This isn’t the nice About Defold dialogue found at the bottom of the Help menu, it’s more blank/default.
Can confirm that I have the same issue on macOS Catalina 10.15.1 running Defold 1.2.164. It’s a bit annoying but understand that it’s not a top priority to get fixed.