In the File button, to the left of Home, you can close a tab or the selected tab's project. But theres no way to close all opened projects from this menu.
Similar with right clicking a tab. You should be able to close all tabs from there too. Or not?
A quicky to add, maybe a "recover last closed tab" option? Similar to browsers tabs do?
As you see this is no bug but just a suggestion that i prefer to throw here.
See you all after my vacations! Good luck with your updates, the 100th release seems promising!