This directory provides the controllers that act as an interface between the
LyX kernel and the GUI-specific implementations of each popup. It also
provides abstract base classes from which GUI-specific implemetations of the
ButtonController and each separate popup should be derived (see
ButtonControlBase.[Ch] and ViewBase.h respectively).

The Controller connects the GUI-specific popup to any appropriate signals and
dispatches any changes in the data to the kernel. It has no knowledge of the
actual instantiation of the GUI-dependent View and ButtonController, which
should therefore be created elsewhere. Once created, the Controller will take
care of their initialisation, management and, ultimately, destruction.

This leaves the GUI-specific popup (and its author!) to worry only about the
data that it has been created to input/modify.

This concept has been instatiated for the Citation dialog only at the moment.
See xforms-new/FormCitation.[Ch] for an xforms-specific View of the dialog.