sorry stworthy, but it isn't working with me,,
see bug panelwidth.png:
as you can see , panel combogrid just shown as straight line, when i set panelWidth with 'auto'.
as my code below:
tipPosition:'top',
url:'#{lookup_menu_path}',
mode:'remote',
method:'get',
fitColumns:true,
panelWidth:'auto',
textField:'namamenu',
idField:'id_menu',
onShowPanel:function(){return rowHeight(this);},
columns:[[{field:'namamenu',title:'Title', width:100,sortable:true}]]
many thanks for the answer