Program: 124042
Project: 124042
Buggy source:
@Override public Control createControl(final Composite subComposite,final IElementParameter param,final int numInRow,final int nbInRow,final int top,final Control lastControl){
  DecoratedField dField=new DecoratedField(subComposite,SWT.BORDER,cbCtrl);
  if (param.isRequired()) {
    FieldDecoration decoration=FieldDecorationRegistry.getDefault().getFieldDecoration(FieldDecorationRegistry.DEC_REQUIRED);
    dField.addFieldDecoration(decoration,SWT.RIGHT | SWT.TOP,false);
  }
  if (param.isRepositoryValueUsed()) {
    FieldDecoration decoration=FieldDecorationRegistry.getDefault().getFieldDecoration(FieldDecorationRegistry.DEC_CONTENT_PROPOSAL);
    decoration.setDescription(Messages.getString("String_Node_Str"));
    dField.addFieldDecoration(decoration,SWT.RIGHT | SWT.BOTTOM,false);
  }
  Control cLayout=dField.getLayoutControl();
  CCombo combo=(CCombo)dField.getControl();
  FormData data;
  combo.setItems(getListToDisplay(param));
  combo.setEditable(true);
  cLayout.setBackground(subComposite.getBackground());
  combo.setEnabled(!param.isReadOnly());
  combo.addSelectionListener(listenerSelection);
  combo.addModifyListener(modifySelection);
  combo.setData(PARAMETER_NAME,param.getName());
  if (elem instanceof Node) {
    combo.setToolTipText(VARIABLE_TOOLTIP + param.getVariableName());
  }
  CLabel labelLabel=getWidgetFactory().createCLabel(subComposite,param.getDisplayName());
  data=new FormData();
  if (lastControl != null) {
    data.left=new FormAttachment(lastControl,0);
  }
 else {
    data.left=new FormAttachment((((numInRow - 1) * MAX_PERCENT) / nbInRow),0);
  }
  data.top=new FormAttachment(0,top);
  labelLabel.setLayoutData(data);
  if (numInRow != 1) {
    labelLabel.setAlignment(SWT.RIGHT);
  }
  data=new FormData();
  int currentLabelWidth=STANDARD_LABEL_WIDTH;
  GC gc=new GC(labelLabel);
  Point labelSize=gc.stringExtent(param.getDisplayName());
  gc.dispose();
  if ((labelSize.x + ITabbedPropertyConstants.HSPACE) > currentLabelWidth) {
    currentLabelWidth=labelSize.x + ITabbedPropertyConstants.HSPACE;
  }
  if (numInRow == 1) {
    if (lastControl != null) {
      data.left=new FormAttachment(lastControl,currentLabelWidth);
    }
 else {
      data.left=new FormAttachment(0,currentLabelWidth);
    }
  }
 else {
    data.left=new FormAttachment(labelLabel,0,SWT.RIGHT);
  }
  data.top=new FormAttachment(0,top);
  cLayout.setLayoutData(data);
  hashCurControls.put(param.getName(),combo);
  Point initialSize=dField.getLayoutControl().computeSize(SWT.DEFAULT,SWT.DEFAULT);
  dynamicProperty.setCurRowSize(initialSize.y + ITabbedPropertyConstants.VSPACE);
  return cLayout;
}

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){
  DecoratedField dField=new DecoratedField(subComposite,SWT.BORDER,cbCtrl);
  if (param.isRequired()) {
    FieldDecoration decoration=FieldDecorationRegistry.getDefault().getFieldDecoration(FieldDecorationRegistry.DEC_REQUIRED);
    dField.addFieldDecoration(decoration,SWT.RIGHT | SWT.TOP,false);
  }
  if (param.isRepositoryValueUsed()) {
    FieldDecoration decoration=FieldDecorationRegistry.getDefault().getFieldDecoration(FieldDecorationRegistry.DEC_CONTENT_PROPOSAL);
    decoration.setDescription(Messages.getString("String_Node_Str"));
    dField.addFieldDecoration(decoration,SWT.RIGHT | SWT.BOTTOM,false);
  }
  Control cLayout=dField.getLayoutControl();
  CCombo combo=(CCombo)dField.getControl();
  FormData data;
  combo.setItems(getListToDisplay(param));
  combo.setEditable(!param.isReadOnly() && !param.isRepositoryValueUsed());
  combo.setEnabled(!param.isReadOnly() && !param.isRepositoryValueUsed());
  cLayout.setBackground(subComposite.getBackground());
  combo.addSelectionListener(listenerSelection);
  combo.addModifyListener(modifySelection);
  combo.setData(PARAMETER_NAME,param.getName());
  if (elem instanceof Node) {
    combo.setToolTipText(VARIABLE_TOOLTIP + param.getVariableName());
  }
  CLabel labelLabel=getWidgetFactory().createCLabel(subComposite,param.getDisplayName());
  data=new FormData();
  if (lastControl != null) {
    data.left=new FormAttachment(lastControl,0);
  }
 else {
    data.left=new FormAttachment((((numInRow - 1) * MAX_PERCENT) / nbInRow),0);
  }
  data.top=new FormAttachment(0,top);
  labelLabel.setLayoutData(data);
  if (numInRow != 1) {
    labelLabel.setAlignment(SWT.RIGHT);
  }
  data=new FormData();
  int currentLabelWidth=STANDARD_LABEL_WIDTH;
  GC gc=new GC(labelLabel);
  Point labelSize=gc.stringExtent(param.getDisplayName());
  gc.dispose();
  if ((labelSize.x + ITabbedPropertyConstants.HSPACE) > currentLabelWidth) {
    currentLabelWidth=labelSize.x + ITabbedPropertyConstants.HSPACE;
  }
  if (numInRow == 1) {
    if (lastControl != null) {
      data.left=new FormAttachment(lastControl,currentLabelWidth);
    }
 else {
      data.left=new FormAttachment(0,currentLabelWidth);
    }
  }
 else {
    data.left=new FormAttachment(labelLabel,0,SWT.RIGHT);
  }
  data.top=new FormAttachment(0,top);
  cLayout.setLayoutData(data);
  hashCurControls.put(param.getName(),combo);
  Point initialSize=dField.getLayoutControl().computeSize(SWT.DEFAULT,SWT.DEFAULT);
  dynamicProperty.setCurRowSize(initialSize.y + ITabbedPropertyConstants.VSPACE);
  return cLayout;
}