@Override
        public void selectionChanged(ICompletionProposal proposal, boolean smartToggle) {
            SQLCompletionActivityTracker activityTracker =
                proposal instanceof SQLQueryCompletionProposal p ? p.getProposalContext().getActivityTracker() :
                proposal instanceof SQLCompletionProposalBase p ? p.getRequest().getActivityTracker() : null;

            if (activityTracker != null) {
                activityTracker.selectionChanged();
            }
        }
This method is incomplete in that it does not implement logic to produce
some context help relevant to SQL. It just hard codes two strings to
demonstrate the action

@see org.eclipse.jface.text.contentassist.IContentAssistProcessor#computeContextInformation(ITextViewer,
     int)
plugins/org.jkiss.dbeaver.ui.editors.sql/src/org/jkiss/dbeaver/ui/editors/sql/syntax/SQLCompletionProcessor.java