What is this line on my dock? I recently upgraded to Yosemite and I seem to have some sort of line on my desktop near the dock that won't go away.  I've changed my background, moved the dock and even rebooted and it stays there.  It looks like something that I can click on and drag up but it doesn't do anything if I click on it.  Did I install something that is causing this?
This is a progress bar under Downloads folder. It sometimes doesn't go away after completing the downloads. One solution for this is to enter this command in Terminal: 

killall Dock


This will reset the Dock.