The following ZK fiddle no longer works in 7.0:
http://zkfiddle.org/sample/24ahj3i/1-Listen-Grid-scrolling

<zk>
<zscript>Object[] o = new Object[50];</zscript>
<hlayout>
<grid id="grid1" width="100px" height="100px">
<rows>
<row forEach="${o }">
<label value="item ${forEachStatus.index}"/>
</row>
</rows>
</grid>
<grid id="grid2" width="100px" height="100px">
<rows>
<row forEach="${o}">
<label value="item ${forEachStatus.index}"/>
</row>
</rows>
</grid>
</hlayout>
<zscript><![CDATA[
grid1.setWidgetListener("onScroll", "this.$f('grid2').ebody.scrollTop = this.ebody.scrollTop;");
]]></zscript>
</zk>