EXTJS Tree panel not loading properly in IE 9

[kavyakn]

Tree panel child nodes are not expanding properly in IE9 . They start expanding from the root and not from their parents . Can you suggest some solution ? Please refer the snapshot.

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here the child nodes of the parent highlighted with blue expand arrow start expanding from top.

[mitchellsimoens]

What Ext JS 4 version?

[kavyakn]

it is EXTJS 4.0.7