Last Friday, I finally installed the newest release of the Xfce desktop environment for Linux, Xfce 4.12. However, after logging in, I saw a horizontal line running on the lower part of my screen from one side to another.
At first I thought (and dreaded) that it’s a driver issue, or that my display is broken, but the line only appeared when I use Xfce; it doesn’t appear when I switch to other desktop vironments like Unity or use Windows.
I Googled and found no issues that resembled mine, but I got the idea to take a screenshot of my screen and see if the line appeared on the result. It was.
A closer look made me notice that the line appeared on top of Cairo Dock, and hovering over the file browser applet made similar lines appeared around it.
I finally found the fix: open Settings, then Window Manager Tweaks and untick the ‘Show shadows under dock windows’ checkbox on the Compositor tab. It would remove shadows from under docks and deskbars.
As a comparison, here’s my desktop with and without shadows under dock windows:
And that’s it! Turned out that the solution was as simple as removing the tick from a checkbox.
Did it work for you? Let me know in the comments!
Nochka's Weekly Tech Findings 
I’ve seen the first issue you mentioned. It doesn’t only affect Docks like Cairo but also Xfce’s own panel when you set it to transparent.
I haven’t seen the other issue but suspect it is a distro problem. You don’t mention which distro you are using but I suggest you raise a bug report there.
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I’m using Ubuntu 14.04 LTS, and I’m planning to file a bug report soon. Never tried it before, but it seems not very hard to do.
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You sir are a gentleman and a scholar. Was tearing my hair out looking for that exact setting for that exact problem.
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It’s good to see that this helps you 😉
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mee too, mee too !!
used docky as a dock and have this annoying line. now it’s fixed, many thanks!
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Thanks, just noticed that line myself today and it was driving me up a wall. Thanks for posting a fix.
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thanks for that helpful tip, it was bugging me all day.. even though I’ve worked with Xubuntu before I got tired of digging through the settings. My orginal instinct was to look through the cairo-dock settings
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You just saved my life, thanks dude!
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You’re welcome!
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Awesome, fixed my problem. Cheers
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Thanks so much. I was about to call the window manager a bust. (Ubuntu 15.10)
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Thank you for posting this, I switched back to using xfwm4 (from using KWIN with XFCE – http://hobo.house/2015/08/14/using-kwin-with-xfce/ ) for a while as KWIN caused issues with some external displays and your post helped me remove that annoying horizontal line so now xfwm4 is flawless.
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I hade the same with the new xubuntu 16.04 LTS. Your post help me alot. Tanks!
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Glad to know that this helps 😉
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Thanks nochkawtf. I was going crazy trying to find what caused this. Googled like mad, but obviously with the wrong keywords. I posted my problem over at Ubuntuforums, where I was pointed toward this article.
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Finally! Thanks, so much, nochkawtf!
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Thank You! The line appeared the same day I installed plank but I didn’t put 2 and 2 together. When taking any application full screen the line went away but it was still driving me crazy. One simple checkbox, I dont think i would have stumbled upon the solution myself.
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Thank you so much!! Had the exact same problem using docky, solution worked perfectly! 🙂 As pm5k00 said, no way i would have found this…
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Thank you very much sir
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Holy Cow! Thank you for saving me buying another monitor…only to have the same problem. The pictures were very helpful here.
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Thanks so much, this helped me out alot. I had just installed mx-16 on GT 5636E desktop pc, dual boot mint 18.1 , I am really liking this OS and I am thankful for your fine instructions!
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Thank you so much I was about to freak out I thought my screen was messed up
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Thank you, that did the trick!
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Thanks buddy… You hit the nail on the head
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Thank you , i thought my display was broken before seeing this post. 🙂
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Great one man. Thanks a lot 🙂
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Tank you man i changed the option before but i forgot that i changed. thank you for helping
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Thank you so much! I booted into Xubuntu an hour or so ago, and there was the exact same bar. Funny thing is, it didn’t appear when I used it earlier today.
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Hi nochkawtf, in first place, thanks for the help with that line, and last, what Icon Theme are you using in this pictures, please? Thanks in advance
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Thanks, it’s great to know this helps you 🙂 Unfortunately, I can’t remember what icon theme I was using in the screenshots. I’ll update this comment as soon as I figure it out.
UPDATE: Looks like it’s Evolvere, especially the “sunken” variant.
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Thank you! Fixed my problem using Plank.
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Thx a lot. I thought it was a Docky’s problem.
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Thanks! That worked like a charm, still trying to figure out how to prevent Docky from crashing when adding the “Session Manager” docklet…
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God bless you mate
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Thank you so much! Fixed my problem in version 4.12 Xfce on Xubuntu 16.04 LTS.
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thanks!!!
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Thanks for sharing this, well explained and very helpful.
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Thank you so much! Fixed my problem in version 4.12 Xfce by Debian
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Thanks!!! I had the same problem and it was driving me up the wall! Just got XFCE, too, so I didn’t have the slighest clue on where to start fixing that problem.
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The horizontal just showed up for me and the setting had somehow become set. Thanks for the fix! (Xubuntu 16.04 here.)
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Thank you so much. Greatly appreciated.
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You should do coast guard, because you are life saver 🙂
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Thank you.
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You’re welcome. I’m glad this fix works for you.
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Thanks, very helpful content
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ouch niceee. I was getting crazy with this error
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another one who owes you a beer! I’m on FreeBSD 12 with XFCE (making a transition from Nomad BSD because that was too fidgety to install in the current version . They had this one licked and it was driving me bonkers.
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Thank you! I love when I found the short and correct way to fix an issue
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Thanks a lot man!
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Yes!! Thank you for this! That line was driving me mad! Using Plank on Manjaro Xfce.
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Gracias!
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Terima Kasih!!!!
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Muchas gracias!! Thank you very much!!!
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It’s very helped to me. Thanks a lot ❤
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Thanks very usefull
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THANK YOU!!!!!
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Thx
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thank you very much
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You’re welcome, glad to see this old trick still works!
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Hi. Just wanted to let you know that I’m using the latest version of Manjaro (XFCE 4.16) with Plank dock and I had this issue. Your solution fixed it. Thanks!
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Hi Bradley, you’re welcome, glad to see this helps you!
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I had this problem on PeppermintOS 11 installed on a Toshiba CB30-102 using Plank dock. Nice easy fix when I found this article!
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