The math node the selection acts on: the node under a NodeSelection, the
inline atom on either side of a caret (before wins, matching how backspace
reads), or a mathBlock the selection sits on or beside. Null when the
selection is nowhere near a formula.
The math node the selection acts on: the node under a
NodeSelection, the inline atom on either side of a caret (before wins, matching how backspace reads), or amathBlockthe selection sits on or beside. Null when the selection is nowhere near a formula.