I don't know if this is a common behavior, or something in my configuration is missing, but my Azure Solution in Visual studio 2012 starts two browser instances every time i hit F5. I think it has to do with how many endpoints i have defined in the "CloudConfiguration" settings.
PS: In a normal web application project this behavior is defined in Project->Propertes->Web->Start Acton->Dont open a page.... . This seems not to work debuging Azure project.
How to disable the auto start?
Yes - two tabs open because you have two endpoints defined. Right-click on the web role and select properties, then under Configuration >> Startup Action - select/deselect the endpoints you want to launch: