Description of problem:
I have installed Fedora 20 live with Xfce desktop that comes with kernel 3.11.10-301.fc20.x86_64 by default. Then installed Docky (a shortcut bar) and it worked fine. Then through updates the kernel got rebased to version 3.15.6-200.fc20.x86_64. After this update I have problems with Docky and I believe it has something to do with the way composition is working.
What exactly is the problem: when I check the 3D view option of Docky I get some light "aura" sticking out from the dock (see Image 1).
After that when I move a window to hover the dock and activate the "Intellihide" effect I get a long light line covering the screen end-2-end. It is approximately 100px in height (see Image 2).

Image 1: https://imagizer.imageshack.us/v2/1360x589q90/539/9c7dc7.png
Image 2: https://imagizer.imageshack.us/v2/1110x586q90/538/7406b2.png

Version-Release number of selected component (if applicable):


How reproducible: always


Steps to Reproduce:
1. Install Fedora 20 Live Xfce Desktop (kernel 3.11.10-301.fc20.x86_64)
2. Install Docky shortcut bar (still no problem).
3. Update to kernel 3.15.6-200.fc20.x86_64.
4. Problem appears.

Actual results: UI changes - Light line appears on the screen.


Expected results: No UI changes.


Additional info:
The problem was reproduced on two different machines. One with the Intel HD Graphics and the other with nVidia graphics card. On the first machine the kernel was manually updated (downloaded from https://apps.fedoraproject.org/packages/kernel) and on the second - through Fedora updates.