I'm using Ext.grid.plugin.CellEditing for editing cells.

The problem is when the data type of a cell is number, after clicking the cell to editing mode, but nothing changing, the cell is marked by red triangle as dirty. This does not happen for string types.

The input in the grid row is json e.g.:
{
"id" : 1,
"name": "Alicia"
}

This didn't happen in ExtJS 3.1. Is it a bug or how can I fix it?