e.g. modify the cell-editing.js example

Code:
    var grid = Ext.create('Ext.grid.Panel', {
        store: store,
        columns: [{
            id: 'common',
            header: 'Common Name',
            dataIndex: 'common',
            flex: 1,
            editor: {
                xtype:'textarea',
                resizable:{ handles:'s', minheight: 50, heightIncrement:20, constrainTo:Ext.getBody() },
                height:200,
                width:250,
                allowBlank: false
            }
When editing starts the Textarea is clipped (worked fine in 4.0.x).
After resizing it is fine.