Icons in the right click menu should be informative

As for now, the right click menu shows the same icon for every window,
e.g.
Firefox shows the firefox icon for all instances of firefox
All open folders in nautilus are shown with the home folder icon (folder with a home)

These icons provide no information about the window at all.
Instead they should display icons that help distinguish the different windows.

Windows in Firefox should be displayed with the icon of the open website, the same that is used when the site is added as a bookmark.
Windows in Nautilus should be displayed with the icons that are also used in Nautilus itself (special icons for home and its subfolders)

This might be useful for other applications as well that are often used in multiple instances.