How to visualize wrong or missing configuration in NM connection editor

Hey,

I would like to ask/discuss what do you think would be a good way how to 
visualize wrong or missing configuration in NM connection editor, because 
there are quite many fields you can set and sometimes users may be wondering 
why they cannot hit the apply button. 

Example 1 - missing password in wifi configuration:
https://jgrulich.fedorapeople.org/wifi_tab_missing_password.png

Example 2 - missing IP address in ipv4 configuration:
https://jgrulich.fedorapeople.org/ipv4_tab_missing_address.png

But there are many cases where this would be needed and some of them may not 
be that obvious like missing password.

One solution could be to use what nm-connection-editor uses for this. They 
highlight the border of the missing/wrong field, see picture below:
https://jgrulich.fedorapeople.org/nm_connection_editor.png

I would personally go for this, but there is no other application using/
requiring something like this, at least none I would be aware of so I'm not 
sure if this will comply with you and our guidelines and I would like to also 
hear other opinions.

Thank you

Regards,
Jan
-- 
Jan Grulich,
Software Engineer, Desktop Team
Red Hat