Program: 145444
Project: 145444
Buggy source:
@Override public boolean render(Context context,String aId,Row value,SafeHtmlBuilder sb){
  LookupModelGridColumn column=LookupModelGridColumn.this;
  JavaScriptObject onRender=column.getOnRender() != null ? column.getOnRender() : column.getGrid().getOnRender();
  if (onRender != null) {
    try {
      PublishedStyle styleToRender=null;
      SafeHtmlBuilder lsb=new SafeHtmlBuilder();
      String toRender=String.valueOf(value);
      PublishedCell cellToRender=calcContextPublishedCell(column.getPublished(),onRender,context,column.getColumnModelRef(),toRender,rowsEntity);
      if (cellToRender != null) {
        styleToRender=cellToRender.getStyle();
        if (cellToRender.getDisplay() != null)         toRender=cellToRender.getDisplay();
      }
      if (toRender == null)       lsb.append(SafeHtmlUtils.fromTrustedString("String_Node_Str"));
 else       lsb.append(SafeHtmlUtils.fromString(toRender));
      styleToRender=grid.complementPublishedStyle(styleToRender);
      String decorId=ControlsUtils.renderDecorated(lsb,aId,styleToRender,sb);
      if (cellToRender != null) {
        if (context instanceof RenderedCellContext) {
          ((RenderedCellContext)context).setStyle(styleToRender);
        }
        LookupModelGridColumn.this.bindGridDisplayCallback(decorId,cellToRender);
        if (cellToRender.getStyle() != null) {
          ModelGridColumn.bindIconCallback(cellToRender.getStyle(),decorId);
        }
      }
    }
 catch (    Exception e) {
      sb.append(SafeHtmlUtils.fromString(e.getMessage()));
    }
    return true;
  }
 else   return false;
}

Fixed version (ground truth):
@Override public boolean render(Context context,String aId,Row value,SafeHtmlBuilder sb){
  LookupModelGridColumn column=LookupModelGridColumn.this;
  JavaScriptObject onRender=column.getOnRender() != null ? column.getOnRender() : column.getGrid().getOnRender();
  if (onRender != null) {
    try {
      PublishedStyle styleToRender=null;
      SafeHtmlBuilder lsb=new SafeHtmlBuilder();
      String toRender=value != null ? ((ModelCombo)getEditor()).getConverter().convert(value.getColumnObject(displayValueRef.getColIndex())) : "String_Node_Str";
      PublishedCell cellToRender=calcContextPublishedCell(column.getPublished(),onRender,context,column.getColumnModelRef(),toRender,rowsEntity);
      if (cellToRender != null) {
        styleToRender=cellToRender.getStyle();
        if (cellToRender.getDisplay() != null)         toRender=cellToRender.getDisplay();
      }
      if (toRender == null)       lsb.append(SafeHtmlUtils.fromTrustedString("String_Node_Str"));
 else       lsb.append(SafeHtmlUtils.fromString(toRender));
      styleToRender=grid.complementPublishedStyle(styleToRender);
      String decorId=ControlsUtils.renderDecorated(lsb,aId,styleToRender,sb);
      if (cellToRender != null) {
        if (context instanceof RenderedCellContext) {
          ((RenderedCellContext)context).setStyle(styleToRender);
        }
        LookupModelGridColumn.this.bindGridDisplayCallback(decorId,cellToRender);
        if (cellToRender.getStyle() != null) {
          ModelGridColumn.bindIconCallback(cellToRender.getStyle(),decorId);
        }
      }
    }
 catch (    Exception e) {
      sb.append(SafeHtmlUtils.fromString(e.getMessage()));
    }
    return true;
  }
 else   return false;
}