Problem with menu drop down. Please help me out !

Hi guys,

I just installed a plugin named “WordPress Thumbnail Slider”. When I activate it there’s no problem. But when I place the short code into my post or into my theme’s php file, my menu drop down stop working. When I hover on my menu which includes a sub menu its not showing anymore. I am not a pro developer. Please help me out. That plugin was last updated on 2014-2-13. What could be the problem??

Thanks in advance ??