This is the interactive implementation of the abstract histogram plotter. This implementation allows the user to change the following properties on the fly:
  1. Number of bars for numerical columns
  2. The size of the bars
  3. The background color
  4. X axis
  5. Aggregation columns
  6. Aggregation method
  7. Show/hide missing value bar
  8. Show/hide empty bars
  9. Layout options
In order to allow this flexibility and to support hiliting the node holds all data in the main memory.