Ext.grid.PagingScroller often uses the `store` from its panel, not the provided one.

[SamuraiJack1]

The Scroller class has the `store` attribute, which is provided by the panel in the `initVerticalScroller` method. However, in several methods (`syncTo/onElScroll`) scroller uses the `store` from panel, and not own reference:

    syncTo: function() {
        var me            = this,
            pnl           = me.getPanel(),
            store         = pnl.store,
            scrollerElDom = this.scrollEl.dom,


    onElScroll: function(e, t) {
        var me = this,
            panel = me.getPanel(),
            store = panel.store,
            pageSize = store.pageSize,
            guaranteedStart = store.guaranteedStart,

In certain advanced situations (like buffering of the tree view) it makes us to override those methods in whole..

[SamuraiJack1]

Bah, and in `setViewScrollTop` scroller uses the store from view