A common issue which happens after clicking on the Export button is that Postbacks don't work. A workaround to avert this issue is to use the following script in the webpart:
<script type="text/javascript">
if (typeof (_spBodyOnLoadFunctionNames) != 'undefined' && _spBodyOnLoadFunctionNames != null) {
_spBodyOnLoadFunctionNames.push("supressSubmitWraper");
}
function supressSubmitWraper() {
_spSuppressFormOnSubmitWrapper = true;
}
</script>