Program: 123768
Project: 123768
Buggy source:
@Override public Control createControl(final Composite subComposite,final IElementParameter param,final int numInRow,final int nbInRow,final int top,final Control lastControl){
  boolean hasScreenshots=false;
  byte[] screenshot=null;
  if (param.getElement() instanceof INode && ((INode)param.getElement()).getExternalNode() != null) {
    String componentType=((INode)param.getElement()).getComponent().getName();
    if ("String_Node_Str".equals(componentType)) {
      IProcess process=((INode)param.getElement()).getProcess();
      if (process instanceof IProcess2) {
        IProcess2 processtmp=(IProcess2)process;
        Item item=processtmp.getProperty().getItem();
        if (item instanceof ProcessItem) {
          ProcessItem processItem=(ProcessItem)item;
          screenshot=(byte[])processItem.getProcess().getScreenshots().get(((INode)param.getElement()).getUniqueName());
          if (screenshot != null) {
            hasScreenshots=true;
          }
        }
 else         if (item instanceof JobletProcessItem) {
          JobletProcessItem jobletItem=(JobletProcessItem)item;
          screenshot=(byte[])jobletItem.getJobletProcess().getScreenshots().get(((INode)param.getElement()).getUniqueName());
          if (screenshot != null) {
            hasScreenshots=true;
          }
        }
      }
    }
  }
  if (hasScreenshots) {
    ImageDescriptor imageDesc=ImageUtils.createImageFromData(screenshot);
    ((INode)param.getElement()).getExternalNode().setScreenshot(imageDesc);
    final Composite compositeImage=new Composite(subComposite,SWT.BORDER);
    final Image image=imageDesc.createImage();
    addResourceDisposeListener(compositeImage,image);
    CLabel labelLabel=getWidgetFactory().createCLabel(subComposite,param.getDisplayName() + "String_Node_Str");
    FormData formDataLabel=new FormData();
    labelLabel.setVisible(true);
    if (numInRow != 1) {
      labelLabel.setAlignment(SWT.RIGHT);
    }
    if (lastControl != null) {
      formDataLabel.left=new FormAttachment(lastControl,0);
    }
 else {
      formDataLabel.left=new FormAttachment((((numInRow - 1) * MAX_PERCENT) / nbInRow),0);
      formDataLabel.top=new FormAttachment(0,top);
    }
    labelLabel.setLayoutData(formDataLabel);
    compositeImage.setToolTipText(param.getDisplayName());
    Point size=new Point(image.getImageData().width,image.getImageData().height);
    FormData formData=new FormData(size.x,size.y);
    formData.top=new FormAttachment(0,top);
    formData.left=new FormAttachment(labelLabel);
    compositeImage.setBackgroundImage(image);
    compositeImage.setLayoutData(formData);
    return compositeImage;
  }
 else {
    return lastControl;
  }
}

Fixed version (ground truth):
@Override public Control createControl(final Composite subComposite,final IElementParameter param,final int numInRow,final int nbInRow,final int top,final Control lastControl){
  boolean hasScreenshots=false;
  byte[] screenshot=null;
  if (param.getElement() instanceof INode && ((INode)param.getElement()).getExternalNode() != null) {
    String componentType=((INode)param.getElement()).getComponent().getName();
    if ("String_Node_Str".equals(componentType)) {
      IProcess process=((INode)param.getElement()).getProcess();
      if (process instanceof IProcess2) {
        IProcess2 processtmp=(IProcess2)process;
        Item item=processtmp.getProperty().getItem();
        if (item instanceof ProcessItem) {
          ProcessItem processItem=(ProcessItem)item;
          screenshot=(byte[])processItem.getProcess().getScreenshots().get(((INode)param.getElement()).getUniqueName());
          if (screenshot != null) {
            hasScreenshots=true;
          }
        }
 else         if (item instanceof JobletProcessItem) {
          JobletProcessItem jobletItem=(JobletProcessItem)item;
          screenshot=(byte[])jobletItem.getJobletProcess().getScreenshots().get(((INode)param.getElement()).getUniqueName());
          if (screenshot != null) {
            hasScreenshots=true;
          }
        }
      }
    }
  }
  if (hasScreenshots) {
    ImageDescriptor imageDesc=ImageUtils.createImageFromData(screenshot);
    ((INode)param.getElement()).getExternalNode().setScreenshot(imageDesc);
    final Composite compositeImage=new Composite(subComposite,SWT.BORDER);
    final Image image=imageDesc.createImage();
    addResourceDisposeListener(compositeImage,image);
    CLabel labelLabel=getWidgetFactory().createCLabel(subComposite,param.getDisplayName() + "String_Node_Str");
    FormData formDataLabel=new FormData();
    labelLabel.setVisible(true);
    if (numInRow != 1) {
      labelLabel.setAlignment(SWT.RIGHT);
    }
    if (lastControl != null) {
      formDataLabel.left=new FormAttachment(lastControl,0);
    }
 else {
      formDataLabel.left=new FormAttachment((((numInRow - 1) * MAX_PERCENT) / nbInRow),0);
      formDataLabel.top=new FormAttachment(0,top);
    }
    labelLabel.setLayoutData(formDataLabel);
    compositeImage.setToolTipText(param.getDisplayName());
    Point size=new Point(image.getImageData().width,image.getImageData().height);
    FormData formData=new FormData((int)(size.x * 0.8),(int)(size.y * 0.8));
    formData.top=new FormAttachment(0,top);
    formData.left=new FormAttachment(labelLabel);
    ImageData data=image.getImageData();
    compositeImage.setLayoutData(formData);
    data=data.scaledTo((int)(size.x * 0.8),(int)(size.y * 0.8));
    Image im=new Image(image.getDevice(),data);
    compositeImage.setBackgroundImage(im);
    return compositeImage;
  }
 else {
    return lastControl;
  }
}