Plugin.stop: refrain from invalidating Isabelle.session -- some actors/dockables out there might still refer to it;
Plugin.stop: refrain from invalidating Isabelle.session -- some actors/dockables out there might still refer to it;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle