I donthink get anything. No set brakes, locking gear etc. Usually it asks if I want to start up before or after pushback.
As I've said, maybe you turned off the Verbosity slider, so you don't see the message from GSX asking to start engine ? Or maybe you set a very high delay between messages, so they don't appear unless you wait a long time ?
And, you don't say which airplane you use. Some planes have additional constraints before allowing to start pushback, and GSX will obviously tell you about them but again, if you either turned down the Verbosity slider, or you increase the time between message to a very high value, you are missing what GSX is trying to tell you about why it cannot continue the pushback.