Hi there....should be simple enough

I have a MODx.combo in a Create window.
I want to preset this to the value of another MODx.combo outside the window.
I have tried this:
{
/* Filter for channels */
xtype: 'modx-combo-channels'
,name: 'channel_id'
,fieldLabel: 'Channel'
,id: 'modx-filter-channels-create'
,emptyText: 'Filter by channel'
,allowBlank: false
,anchor: '90%'
,value: Ext.getCmp('modx-filter-channels').getValue()
}
This seems to work for the first them I open the create window, but each time after the value in the create form is set to the first (IE it does not update if I change the other combo)
Any thoughts?
[ed. note: jusmeig last edited this post 14 years, 5 months ago.]