KaJaSim feature idea: electric parenthesis-like behavior for bond identifiers

[hmedina]

In Kappa syntax, bonds are denoted with "!n", with "n" an integer identifier. These are always paired, with a single pair before/after the operator "->". If the bond is added, the "!n" will only be present in the RHS, if the bond is removed only in the LHS, if preserved will be in both LHS and RHS.

In long rules, it is easy to loose track of where bonds start or end. It would be useful to, when the user mouse overs / selects / highlights one end, the corresponding end lights up.

When rules are very long, the corresponding end might be beyond the screen's edge. A way of dealing with this could be with a small "pop-up" that hovers at the edge of the editor and shows the site where the bond ends up.