Can't figure out how to correctly install .app
Apparently you should not drag the app to the launchpad, instead, drag the app to the application folder (open a finder window), or just do a $ cp /from /to.

So the process is:


Open DMG (it mounts)
Drag .app (and possibly other files) to your "Applications" folder
Unmount/Eject the DMG
Ctrl+click (right-click) to "open" so you can approve the app