Proportional Editing for multiple objects

Since Blender 2.80 it is possible to edit multiple objects together in Edit Mode.
One feature that I am missing, though, is to edit them using Proportional Editing.

I also asked for this on Pablo's Blender Today Live stream:
youtu.be/inlm6Emh3tc
blender.community/c/today/cHcbbc

Even if only vertices of one object are selected, it should be possible to have all objects in Edit Mode to be affected by Proportional Editing.

This is what I would expect to be the default behavior if someone enters Edit Mode and enables Proportional Editing.
If someone doesn't wish to edit objects together, one can simply not select them before entering Edit Mode.

Alternatively the Proportional Editing menu can be extended with a new option, e.g.: "All Objects", to preserve the old behavior if that option is not used:

Related Maniphest Task and Differential in development:
developer.blender.org/T61777
developer.blender.org/D5163