code: private void jComboBoxLineWidthActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jComboBoxLineWidthActionPerformed
          float lineWidth;
          try {
              lineWidth = Float.parseFloat(jComboBoxLineWidth.getSelectedItem().toString());
          } catch (NumberFormatException ex) {
              lineWidth = 1.0f;
          }
          parent.getGraphPanelChart().getChartSettings().setLineWidth(lineWidth);
          refreshGraphPreview();
      }
docs: GEN-LAST:event_jCheckBoxAutoExpandActionPerformed