Seamless mode window sharing

[Mauricius]

I've read somewhere long ago about a feature that allows the user to use the Host system's task switcher (Alt+Tab) to switch between the Guest's windows. I don't know if this feature actually existed, but since it would be quite useful to avoid having to remember which system I'm currently in before instinctively pressing alt+tab to change to another window, and it doesn't seem like a hard feature to implement, are there any plans to introduce it? Or maybe some kind of extension that already adds this functionality.

I know that Seamless mode has been broken for quite a long time, but even without proper Seamless mode support, shared task switcher would be a very useful addition.