Contains core class implementations for blocks associated with the chart representation. A chart definition must contain at least one plot block, one title block, one legend block and any number of other blocks. By default, all blocks are laid out at the same Z-order but the containment hierarchy may be altered. The layout manager attempts to compute a 'preferred size' for the title and legend and stretches the plot area giving it all available space.

Note that a client area class is associated with a region nested within the main block structure.