Changing the current language from the UI does not preserve the query string of the current URL

A clear example where this causes big problems is the space index that has an URL of the form:

http://localhost:8080/xwiki/bin/view/Main/SpaceIndex?space=Test

But when changing language, i.e. pressing the language button in the top-right of the UI, you get to the following URL:

http://localhost:8080/xwiki/bin/view/Main/SpaceIndex?language=ro

...effectively landing on a different space (Main) than the one you were on (Test).

This can significantly break applications that rely on query strings.