avoid somewhat heavy rebuilding of SortedMap via map where plain iteration is sufficient; more elementary level_list: avoid stack overflow; prefer elementary graph operations; tuned;

clarified long_names -- conform to usual Isabelle practice of not analysing internal names;

more precise repaint and revalidate -- the latter is important to keep in sync with content update;

tuned;

prefer synchronous Mutator_Event.Bus on Swing_Thread;

more direct tooltip content;

tuned;

use Pretty_Tooltip for Graphview_Panel; tuned signature;