ExtJS 4.1.2
Architect 2.1.0

Problem: I want a tree grid panel, with an editable column combobox.
So I want to have a CellEditting plugin on the tree.
In architect, this is where my issue begins.
I can't drag the cell editing feature from the toolbox to the project inspector over the tree panel.
That's fine, so I went to create a custom property for plugins.
When I do that, as soon as I create the desired array object, Architect turns it into a string instead of an object.
It seems to do this as soon as I use Ext.create().
I'm copying and pasting the code that Architect has used for a cell edit plugin elsewhere.
This is exactly what I'm putting into the plugin, in the main window, as an array type:
Code:
[ 
Ext.create('Ext.grid.plugin.CellEditing', {
    ptype: 'cellediting',
    clicksToEdit: 1
    })
]
And this is the result:
Code:
plugins: '[ \nExt.create(\'Ext.grid.plugin.CellEditing\', {\n    ptype: \'cellediting\',\n    clicksToEdit: 1\n    })\n]',
Is this a bug?

Can anyone suggest how to sidestep this in the short term so that I can create a cell editable tree panel?

Thanks

Gareth