The element implements a dialog of user calculation of the selected graph parameter for the graphically visible data. The user is given an option to select calculations from the built-in library, the privileged user ("root" or in the "ITW" group) has the opportunity to edit or write their own calculation procedure.

In general, the built-in library currently contains the following functions of the user calculation:
- Sum, at hour.
- Average and range.

Author: Roman Savochenko <roman@oscada.org>
Version: 1.0.2
License: GPLv2