Program: 51848
Project: 51848
Buggy source:
@Bindable public <T>void setElements(Collection<T> elements){
  try {
    this.elements=elements;
    suppressEvents=true;
    prevSelectionPos=-1;
    this.getRootChildren().removeAll();
    for (    Binding b : expandBindings) {
      b.destroyBindings();
    }
    this.expandBindings.clear();
    for (    TreeItemDropController d : this.dropHandlers) {
      XulDragController.getInstance().unregisterDropController(d);
    }
    dropHandlers.clear();
    if (elements == null || elements.size() == 0) {
      suppressEvents=false;
      updateUI();
      return;
    }
    try {
      if (table != null) {
        for (        T o : elements) {
          XulTreeRow row=this.getRootChildren().addNewRow();
          int colSize=this.getColumns().getChildNodes().size();
          for (int x=0; x < colSize; x++) {
            XulComponent col=this.getColumns().getColumn(x);
            XulTreeCol column=((XulTreeCol)col);
            final XulTreeCell cell=(XulTreeCell)getDocument().createElement("String_Node_Str");
            addBindings(column,(GwtTreeCell)cell,o);
            row.addCell(cell);
          }
        }
      }
 else {
        for (        T o : elements) {
          XulTreeRow row=this.getRootChildren().addNewRow();
          ((XulTreeItem)row.getParent()).setBoundObject(o);
          addTreeChild(o,row);
        }
      }
    }
 catch (    XulException e) {
      Window.alert("String_Node_Str" + e);
      System.out.println(e.getMessage());
      e.printStackTrace();
    }
catch (    Exception e) {
      Window.alert("String_Node_Str" + e);
      System.out.println(e.getMessage());
      e.printStackTrace();
    }
    suppressEvents=false;
    this.clearSelection();
    updateUI();
  }
 catch (  Exception e) {
    System.out.println(e.getMessage());
    e.printStackTrace();
  }
}

Fixed version (ground truth):
@Bindable public <T>void setElements(Collection<T> elements){
  try {
    this.elements=elements;
    suppressEvents=true;
    prevSelectionPos=-1;
    if (this.getRootChildren() != null) {
      this.getRootChildren().removeAll();
    }
    this.elements=elements;
    for (    Binding b : expandBindings) {
      b.destroyBindings();
    }
    this.expandBindings.clear();
    for (    TreeItemDropController d : this.dropHandlers) {
      XulDragController.getInstance().unregisterDropController(d);
    }
    dropHandlers.clear();
    if (elements == null || elements.size() == 0) {
      suppressEvents=false;
      updateUI();
      return;
    }
    try {
      if (table != null) {
        for (        T o : elements) {
          XulTreeRow row=this.getRootChildren().addNewRow();
          int colSize=this.getColumns().getChildNodes().size();
          for (int x=0; x < colSize; x++) {
            XulComponent col=this.getColumns().getColumn(x);
            XulTreeCol column=((XulTreeCol)col);
            final XulTreeCell cell=(XulTreeCell)getDocument().createElement("String_Node_Str");
            addBindings(column,(GwtTreeCell)cell,o);
            row.addCell(cell);
          }
        }
      }
 else {
        for (        T o : elements) {
          XulTreeRow row=this.getRootChildren().addNewRow();
          ((XulTreeItem)row.getParent()).setBoundObject(o);
          addTreeChild(o,row);
        }
      }
    }
 catch (    XulException e) {
      Window.alert("String_Node_Str" + e);
      System.out.println(e.getMessage());
      e.printStackTrace();
    }
catch (    Exception e) {
      Window.alert("String_Node_Str" + e);
      System.out.println(e.getMessage());
      e.printStackTrace();
    }
    suppressEvents=false;
    this.clearSelection();
    updateUI();
  }
 catch (  Exception e) {
    System.out.println(e.getMessage());
    e.printStackTrace();
  }
}