Extjs grid special character issues

Question

I am using ExtJS 3, I am entering special characters like "&,<,>" in the Textfield of a grid cell, and when I release that cell then that special character converts into an empty string. It seems like grid does not support special characters (&,<,>).

The code below runs while I edit the grid cell.

new Ext.grid.GridEditor(new Ext.form.TextField({
  cls:'grid-field-editor' ,
  allowBlank: field.toLowerCase() !== "wr_default",
  blankText:resources.getMsg("required_field") ,
  regex:new RegExp(Ext.util.Format.trim("^(?!@#$)([undefined]|[!%* |^=+$'-,':.~]){1,2}$")),
  regexText:resources.getMsg("Value does not match parameter.") + " " + Ext.util.Format.trim("^(?!@#$)([undefined]|[!%*?|^=+$'-,':.~]){1,2}$")
}))