Weird behaviour of scrollbar in IE

<tabbox width="100%" height="100%" vflex="1">
    <tabs>
        <tab label="General Info" id="generalInfo"/>
        <tab label="Author/Publisher/etc." id="authorPublisherEtc"/>
        <tab label="Physical description" id="physicalDescription"/>
        <tab label="Subjects/Contents description" id="subjectsContentsDescription" />
        <tab label="Purchase/price info" id="purchasePriceInfo"/>
    </tabs>
    <tabpanels>
        <tabpanel style="overflow:auto;">
            <include src="tabs/general_info.zul"/>
        </tabpanel>
        <tabpanel style="overflow:auto;">
            <include src="tabs/author_publisher_etc.zul"/>
        </tabpanel>
        <tabpanel style="overflow:auto;">
        	<include src="tabs/physical_description.zul"/>
        </tabpanel>
        <tabpanel style="overflow:auto;">
        	<include src="tabs/subjects_contents_description.zul"/>
        </tabpanel>
        <tabpanel style="overflow:auto;">
        	<include src="tabs/purchase_price_info.zul"/>
        </tabpanel>
    </tabpanels>
</tabbox>