Program: 65997
Project: 65997
Buggy source:
@Override protected Composite getComponent(Composite parent){
  cmpContent=new Composite(parent,SWT.NONE);
{
    GridLayout glMain=new GridLayout();
    glMain.numColumns=2;
    cmpContent.setLayout(glMain);
  }
  Group grpLine=new Group(cmpContent,SWT.NONE);
  GridLayout glLine1b=new GridLayout(2,false);
  grpLine.setLayout(glLine1b);
  grpLine.setLayoutData(new GridData(GridData.FILL_BOTH));
  grpLine.setText(Messages.getString("String_Node_Str"));
  btnCatLabels=new TristateCheckbox(grpLine,SWT.NONE);
{
    btnCatLabels.setText(Messages.getString("String_Node_Str"));
    GridData gd=new GridData(GridData.FILL_VERTICAL);
    gd.horizontalSpan=2;
    btnCatLabels.setLayoutData(gd);
    btnCatLabels.setSelectionState(series.isSetShowCatLabels() ? (series.isShowCatLabels() ? TristateCheckbox.STATE_SELECTED : TristateCheckbox.STATE_UNSELECTED) : TristateCheckbox.STATE_GRAYED);
    btnCatLabels.addListener(SWT.Selection,this);
  }
  LabelAttributesContext clattributesContext=new LabelAttributesContext();
  clattributesContext.isPositionEnabled=false;
  clattributesContext.isFontAlignmentEnabled=false;
  clattributesContext.isVisibilityEnabled=ChartUIExtensionUtil.canEnableUI(btnCatLabels);
  if (series.getCatLabel() == null) {
    org.eclipse.birt.chart.model.component.Label lab=LabelImpl.create();
    series.setCatLabel(lab);
  }
  catLabelAttr=new LabelAttributesComposite(grpLine,SWT.NONE,getContext(),clattributesContext,null,null,series.getCatLabel(),getChart().getUnits());
  GridData cla=new GridData(GridData.FILL_HORIZONTAL);
  cla.horizontalSpan=2;
  catLabelAttr.setLayoutData(cla);
  catLabelAttr.addListener(this);
  catLabelAttr.setDefaultLabelValue(LabelImpl.createDefault());
  btnCLFormatSpecifier=new Button(grpLine,SWT.PUSH);
{
    GridData gdBTNFormatSpecifier=new GridData();
    gdBTNFormatSpecifier.horizontalIndent=-3;
    gdBTNFormatSpecifier.horizontalSpan=2;
    btnCLFormatSpecifier.setLayoutData(gdBTNFormatSpecifier);
    btnCLFormatSpecifier.setToolTipText(Messages.getString("String_Node_Str"));
    btnCLFormatSpecifier.addListener(SWT.Selection,this);
    btnCLFormatSpecifier.setText(Messages.getString("String_Node_Str"));
  }
  updateUIState();
  return cmpContent;
}

Fixed version (ground truth):
@Override protected Composite getComponent(Composite parent){
  cmpContent=new Composite(parent,SWT.NONE);
{
    GridLayout glMain=new GridLayout();
    glMain.numColumns=2;
    cmpContent.setLayout(glMain);
  }
  Group grpLine=new Group(cmpContent,SWT.NONE);
  GridLayout glLine1b=new GridLayout(2,false);
  grpLine.setLayout(glLine1b);
  grpLine.setLayoutData(new GridData(GridData.FILL_BOTH));
  grpLine.setText(Messages.getString("String_Node_Str"));
  btnCatLabels=getContext().getUIFactory().createChartCheckbox(grpLine,SWT.NONE,defSeries.isShowCatLabels());
{
    btnCatLabels.setText(Messages.getString("String_Node_Str"));
    GridData gd=new GridData(GridData.FILL_VERTICAL);
    gd.horizontalSpan=2;
    btnCatLabels.setLayoutData(gd);
    btnCatLabels.setSelectionState(series.isSetShowCatLabels() ? (series.isShowCatLabels() ? ChartCheckbox.STATE_SELECTED : ChartCheckbox.STATE_UNSELECTED) : ChartCheckbox.STATE_GRAYED);
    btnCatLabels.addListener(SWT.Selection,this);
  }
  LabelAttributesContext clattributesContext=new LabelAttributesContext();
  clattributesContext.isPositionEnabled=false;
  clattributesContext.isFontAlignmentEnabled=false;
  clattributesContext.isVisibilityEnabled=ChartUIExtensionUtil.canEnableUI(btnCatLabels);
  if (series.getCatLabel() == null) {
    org.eclipse.birt.chart.model.component.Label lab=LabelImpl.create();
    series.setCatLabel(lab);
  }
  catLabelAttr=new LabelAttributesComposite(grpLine,SWT.NONE,getContext(),clattributesContext,null,null,series.getCatLabel(),getChart().getUnits(),defSeries.getCatLabel());
  GridData cla=new GridData(GridData.FILL_HORIZONTAL);
  cla.horizontalSpan=2;
  catLabelAttr.setLayoutData(cla);
  catLabelAttr.addListener(this);
  catLabelAttr.setDefaultLabelValue(LabelImpl.createDefault());
  btnCLFormatSpecifier=new Button(grpLine,SWT.PUSH);
{
    GridData gdBTNFormatSpecifier=new GridData();
    gdBTNFormatSpecifier.horizontalIndent=-3;
    gdBTNFormatSpecifier.horizontalSpan=2;
    btnCLFormatSpecifier.setLayoutData(gdBTNFormatSpecifier);
    btnCLFormatSpecifier.setToolTipText(Messages.getString("String_Node_Str"));
    btnCLFormatSpecifier.addListener(SWT.Selection,this);
    btnCLFormatSpecifier.setText(Messages.getString("String_Node_Str"));
  }
  updateUIState();
  return cmpContent;
}