DropBox displays junk icon file

Hello,

This is only happening in Yosemite and only when opening DropBox via the dock (like the Downloads folder)

http://forums.macrumors.com/attachment.php?attachmentid=509194&stc=1&d=1414456863

The "icon" file can be removed by dragging it anywhere outside the folder, where it simply disappears in the same way that you can remove an app from the dock.

However, the "icon" file returns after every reboot.

Any ideas on how to get rid of this junk file for good?

Thanks.