Nope, the RGB-LED is under system control, unless your code takes over by means of RGB.control(true);. So any light you see is by the system.
If you want an indication of your oen code running you can use the little blue D7 LED or take over RGB control.
BTW: Why do you do goToSetupMode() twice? (STARTUP & setup())
Could you also show the declaration of button and buttonEvent?
For breathing blue (or any other issue that has catchy search terms) you could have used the forum search, which e.g came up with this
After some time Photon breathes blue