Vlad
Vlad in Safari the default is similar, up to a point: when you use the close button on the last tab, it closes the tab and immediately reopens the “start page” (or whatever is configured); or when using cmd-w it closes the window unless the user defines a keyboard shortcut for Safari that overloads cmd-w to be only “Close Tab”. I tried this work around with Orion but the system keyboard shortcuts are ignored.