Exactly - now I have a button stuck in the header that I can't edit/delete.

same problem here - now I just have the button stuck and can't edit it.

Thanks Sergey - just tried it again but used a password this time and it worked. Didn't realize that was required.

Yes, and I was able to send a Push to my phone using Parse and the same certificate so I know the certificate itself isn't the issue (although possibly a setting in the App Builder that relates to the certificate).