I am currently applying for a H1B visa transfer to work for another company and the petition should be filed in the next few days, allowing me to start working for the new employer. There is a slight chance that I may still want to continue working for my current employer - and as I read on your website, this is allowed. Would you know if there is any public document (e.g., issued by USCIS) that indicates that this is indeed legal? Basically I would like to just have this in hand if I would be needing to explain this to my current/new employer.