Program: 52710
Project: 52710
Buggy source:
private void addDesiredAllocationColumn(ShowHideColumnHelper support){
  Column column=new Column("String_Node_Str",Messages.ColumnDesiredAllocation,SWT.RIGHT,70);
  column.setDescription(Messages.ColumnDesiredAllocation_Description);
  column.setLabelProvider(new ColumnLabelProvider(){
    @Override public String getText(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() ? Values.Weight.format(node.getWeight()) : node.isUnassignedCategory() ? Messages.LabelNotAvailable : null;
    }
    @Override public Color getForeground(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? Display.getDefault().getSystemColor(SWT.COLOR_BLACK) : null;
    }
    @Override public Color getBackground(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? getWarningColor() : null;
    }
    @Override public Image getImage(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? Images.QUICKFIX.image() : null;
    }
  }
);
  new ValueEditingSupport(TaxonomyNode.class,"String_Node_Str",Values.Weight){
    @Override public boolean canEdit(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      if (node.isAssignment() || node.isUnassignedCategory())       return false;
      return super.canEdit(element);
    }
  }
.addListener(new ModificationListener(){
    @Override public void onModified(    Object element,    Object newValue,    Object oldValue){
      onWeightModified(element,newValue,oldValue);
    }
  }
).attachTo(column);
  support.addColumn(column);
}

Fixed version (ground truth):
private void addDesiredAllocationColumn(ShowHideColumnHelper support){
  Column column=new Column("String_Node_Str",Messages.ColumnDesiredAllocation,SWT.RIGHT,70);
  column.setDescription(Messages.ColumnDesiredAllocation_Description);
  column.setLabelProvider(new ColumnLabelProvider(){
    @Override public String getText(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() ? Values.Weight.format(node.getWeight()) : node.isUnassignedCategory() ? Messages.LabelNotAvailable : null;
    }
    @Override public Color getForeground(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? Display.getDefault().getSystemColor(SWT.COLOR_BLACK) : null;
    }
    @Override public Color getBackground(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? getWarningColor() : null;
    }
    @Override public Image getImage(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      return node.isClassification() && getModel().hasWeightError(node) ? Images.QUICKFIX.image() : null;
    }
  }
);
  new ValueEditingSupport(TaxonomyNode.class,"String_Node_Str",Values.Weight){
    @Override public boolean canEdit(    Object element){
      TaxonomyNode node=(TaxonomyNode)element;
      if (node.isAssignment() || node.isUnassignedCategory())       return false;
      return super.canEdit(element);
    }
  }
.addListener((element,newValue,oldValue) -> onWeightModified(element,newValue,oldValue)).attachTo(column);
  support.addColumn(column);
}