Problem

I tried to post this on discourse, but that forum is too restrictive in flagging my question as spam (just because I am linking to the specific lines of code to provide context).. so here goes:

it used to be that Axes.get_shared_x_axes() returned a cbook.Grouper() which had a .join() method, but now it is returning an cbook.GrouperView() that is IMMUTABLE. It is breaking my tool and I don't even understand the rationale for such backward incompatible change.

regardless, I need a workaround that would continue to work with future versions of matplotlib. Much appreciate your help in pointing me to the right methods and properties to achieve the same effect as this.

thanks very much.

Proposed solution

revert to the previous behaviour of Axes.get_shared_x_axes() returning a mutable Grouper