Weird behavior on listgrid's filter editor when useing advanced criteria

[yz742000]

1. using smartclient js library 7.0rc2

2. tested on firefox12.0

3. strictly a clientside issue, if I set my listgrid initialCriteria to be a simple criteria, like {'exp_game_id': '$game_id', 'exp_name': '$experiment_name' }, the filter editor behaves properly, but when I try to use advanced criteria, like
{
_constructor:'AdvancedCriteria',
operator:'or',
criteria:[
// this is a Criterion
{ fieldName:'is_new_d', operator:'greaterThan', value:'0' },
{ operator:'and', criteria:[
{ fieldName:'exp_name', operator:'iContains', value:'$experiment_name' },
{ fieldName:'exp_game_id', operator:'equals', value: '$game_id' }
]
}
]
}

the filter editor shows properly, and the editor cell won't take any keyboard input even it still allow mouse focus