Can we have a fence insertion of source and destination arrows? Inserting a source or destination arrow one at a time is tedious. The code defined for the source or destination would assume that the number gets indexed alphanumerically e.g. L1, L2, L3; U, V, W; 1, 2, 3;
This should not be a new multiple insertion command but a tick box within the current dialogue. In otherwords do not follow the example of multiple insert of symbols.