Program: 91731
Project: 91731
Buggy source:
private void createLabelVariablesContainer(final Composite container){
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.CENTER).grab(false,false).span(3,1).applyTo(new Label(container,SWT.NONE));
  final Label envVarLabel=new Label(container,SWT.NONE);
  envVarLabel.setText(WizardMessages.getString("String_Node_Str"));
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.CENTER).grab(true,false).span(COLUMNS,1).applyTo(envVarLabel);
  final TableViewer labelVariablesTableViewer=createLabelVariablesTable(container);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).hint(200,100).applyTo(labelVariablesTableViewer.getTable());
  final Composite buttonsContainers=new Composite(container,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(false,false).applyTo(buttonsContainers);
  GridLayoutFactory.fillDefaults().numColumns(1).margins(0,0).spacing(SWT.DEFAULT,0).applyTo(buttonsContainers);
  final Button addButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(addButton);
  addButton.setText(WizardMessages.getString("String_Node_Str"));
  addButton.setEnabled(true);
  addButton.addSelectionListener(onAddLabelVariable(labelVariablesTableViewer));
  final Button editButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(editButton);
  editButton.setText(WizardMessages.getString("String_Node_Str"));
  editButton.setEnabled(true);
  editButton.addSelectionListener(onEditLabelVariable(labelVariablesTableViewer));
  editButton.setEnabled(false);
  final Button removeButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(removeButton);
  removeButton.setText(WizardMessages.getString("String_Node_Str"));
  removeButton.addSelectionListener(onRemoveLabelVariable(labelVariablesTableViewer));
  removeButton.setEnabled(false);
  ViewerSupport.bind(labelVariablesTableViewer,model.getLabelVariables(),BeanProperties.values(LabelVariableModel.class,LabelVariableModel.NAME,LabelVariableModel.VALUE));
  labelVariablesTableViewer.addSelectionChangedListener(onSelectionChanged(editButton,removeButton));
}

Fixed version (ground truth):
private void createLabelVariablesContainer(final Composite container){
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.CENTER).grab(false,false).span(3,1).applyTo(new Label(container,SWT.NONE));
  final Label envVarLabel=new Label(container,SWT.NONE);
  envVarLabel.setText(WizardMessages.getString("String_Node_Str"));
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.CENTER).grab(true,false).span(COLUMNS,1).applyTo(envVarLabel);
  final TableViewer labelVariablesTableViewer=createLabelVariablesTable(container);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.FILL).grab(true,true).hint(200,100).applyTo(labelVariablesTableViewer.getTable());
  final Composite buttonsContainers=new Composite(container,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(false,false).applyTo(buttonsContainers);
  GridLayoutFactory.fillDefaults().numColumns(1).margins(0,0).spacing(SWT.DEFAULT,0).applyTo(buttonsContainers);
  final Button addButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(addButton);
  addButton.setText(WizardMessages.getString("String_Node_Str"));
  addButton.setEnabled(true);
  addButton.addSelectionListener(onAddLabelVariable(labelVariablesTableViewer));
  final Button editButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(editButton);
  editButton.setText(WizardMessages.getString("String_Node_Str"));
  editButton.setEnabled(true);
  editButton.addSelectionListener(onEditLabelVariable(labelVariablesTableViewer));
  editButton.setEnabled(false);
  final Button removeButton=new Button(buttonsContainers,SWT.NONE);
  GridDataFactory.fillDefaults().align(SWT.FILL,SWT.TOP).grab(true,false).applyTo(removeButton);
  removeButton.setText(WizardMessages.getString("String_Node_Str"));
  removeButton.addSelectionListener(onRemoveLabelVariable(labelVariablesTableViewer));
  removeButton.setEnabled(false);
  ViewerSupport.bind(labelVariablesTableViewer,model.getLabelVariables(),BeanProperties.values(LabelVariableModel.class,LabelVariableModel.NAME,LabelVariableModel.VALUE));
  labelVariablesTableViewer.addSelectionChangedListener(onSelectionChanged(editButton,removeButton));
}