Funcunit tests does not fully passed under Phantomjs

Hi, I just forked funcunit. but find a problem. All funcunit tests can pass in latest chrome. But when I try to automate them using phantomjs. It failed at test `"Drag To" (syn_test.js)`. I spent hours on this issue but cannot figure out what is the cause.

I'm using grunt and have tried `testee` and`grunt-contrib-qunit`, both return same errors. It seems the `dropover` event listener never fired. Please help me find the causes of this problem. Thank you!