How to retain previous filter on checkbox extjs 4.1

Hey everyone... I am trying to use this checkbox filter... where a user clicks and then shows list of states on a grid that's only cold... when the user unchecks, I want the store to be back on the previous state... I don't want to use the store.clearfilter() because it just clears my previous filter... I want to retain the previous filter (which is triggered from another combox)... Here's my code that i am trying to use.. but it says

Code:

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TypeError: a.getRoot.call(a, d) is undefined

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please help... is there another way to implement this? thanks

Code:

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    items: [{
                    xtype: 'checkboxfield',
                    boxLabel: 'Show only Cold State',
                    scope: this,
                    handler: function (field, value) {
                        scope: this,
                        this.checkValue = field.getValue();
                        console.log(this.checkValue);
                        if (this.checkValue == true) {
                            var tempstore1 = Ext.getCmp('GridArea1').store;
                                tempstore1.filters.add('CheckBoxFilter', new Ext.util.Filter({
                                    property: 'Cold',
                                    value: 'Yes',
                                    root: 'myTable'
                                }));
                                console.log('here');
                                tempstore1.load();
                        }
                        else if (this.checkValue == false) {
                                this.store.filters.removeAtKey('CheckBoxFilter');
                        }
                    },

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Some code that may help you:

Code:

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    clearFilter: function() {
        var store = this.store,
            filter = this.activeFilter,
            filters = store.filters,
            remaining;
           
        if (filter) {
            if (filters.getCount() > 1) {
                // More than 1 existing filter
                filters.remove(filter);
                remaining = filters.getRange();
            }
            store.clearFilter(true);
            if (remaining) {
                store.filter(remaining);
            }
        }
        return !!filter;
    },

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