Knowledge Base Answer ID 408 says Open URL script step is not working when used via Instant Web Purblishing. Yet I read all kinds of posts here about using it in that context. I thought I had used this in some earlier development but this answer says it has not been working since FileMaker 7.x.
I tried it just now and it failed noting"
"A script step attempted to open a url, but failed because popup windows are being blocked by your browser. Please disable popup blocking and try again."
Am I missing something here?