#97 Tab context menu not aware of project switch

[Riot]

If you have multiple projects open, and open a new file in the editor, you can right-click its tab to select "add this file to the current project":

However, if you have multiple projects open, this is not an option after you've added it to the first project. Opening it from the other project's file browser just shows it as if it were in this project's tree:

However, "show file in project tree" takes you to the other project, not your currently selected one.

Desired behaviour would be at minimum to allow the "add file to current project" dialogue to appear for each project; a better solution would be, in the case of having multiple projects open, to have a pop-out submenu to select which project to add the file to the tree of - or an option to add to all open projects.