You can open Compose in a new tab with Control-click for Win/Linux or Cmd-click for Mac. You can also click on the Compose button normally, then click on the "

You can open Compose in a new tab with Control-click for Win/Linux or Cmd-click for Mac. You can also click on the Compose button normally, then click on the "In new window" icon, in the upper right hand corner. Most web browsers then offer the ability to drag that new window back into your main browser window which turns it into a tab. Kind of a hassle, but it does work, and someone might find this information useful...