A. In order for a diagram to be active (ie. not greyed out) make sure that firstly, the dataset contains the elements required by the diagram in some form and that secondly, the element columns have been aliased in the Data>Column Properties dialog.
In this dialog all of the columns in the dataset listed on the left hand side. If they are already aliased then they will have a green dot next to them. If they are not aliased then click on the Guess Aliases button to automatically match your column names with the standard ioGAS ones. Please check each one to make sure that the correct element/unit combination has been assigned to the columns. Close this dialog and go back to the diagrams menu and the diagrams should now be available for selection.
If only selected diagrams are greyed out then it means that the required element columns which need to be used in the diagram axes are missing from the dataset. Hover the cursor over the greyed out diagram to view what elements are missing. If the variables are in the dataset check that they are not set as text columns.