Lacking from the simple API of System`Utilities`HashTable is a method to enumerate the keys/values. ...
Mathematica has a lot of very useful undocumented features. For example a hash table, a built-in list of compilable functions, additional options to CurrentValue, ...
Background: I have only recently begun programming GUIs in Mathematica, so I have a continuous need for custom controls. I needed a scrollable list control and with the help of Google I found a ...