void refreshTextSelection(){
        ITextSelection selection = (ITextSelection)getSelection();
        fireSelectionChanged(selection.getOffset(), selection.getLength());
    }
Creates an instance of this class with the given parameters.

@param parent the SWT parent control
@param ruler the vertical ruler (annotation area)
@param overviewRuler the overview ruler
@param showsAnnotationOverview <code>true</code> if the overview ruler should be shown
@param styles the SWT style bits
plugins/org.jkiss.dbeaver.ui.editors.sql/src/org/jkiss/dbeaver/ui/editors/sql/SQLEditorSourceViewer.java