Settings,download,bookmarks in new tab instead of new window

I think to avoid multiple windows while browsing Firefox created tabs, so at one place we can see multiple windows(in tabs)with no need to switch between windows.

now to access Download, Bookmarks, History or Options we still use different windows, can these items be placed at one place or on one tab similar to Add-on tab, do we really need window for above items

Regards,
Lelin