title: kendogrid filter menu closing on mouseleave
body: <p>in a kendogrid with <code>kendogrid.columnMenu: true</code> like this <a href="http://jsbin.com/AsEtoDik/2" rel="noreferrer">http://jsbin.com/AsEtoDik/2</a></p>
  
  <p>there's a very annoying behavior: when you try to set a filter and the mouse goes out of the filter panel, it closes. It happens a lot especially filtering on a date column.</p>
  
  <p>I guess this is intended but it's not very user friendly. I thought about setting a timer after the mouseleave event, delaying the closure of the menu, in jQuery but it looks rather difficult and I'd appreciate some help or suggestion</p>