I am using Ubuntu 18.04 on a Dell XPS 13 (2018) that has a HiDPI (UHD) Screen (3480 x 2160), I am then connecting to a UHD Dell 34" Monitor (3440 x 1440) via a USB-C DisplayPort cable.

All the screenshots here are using Wayland - I have also tried using X, but switched to Wayland as that supports separate scaling on the monitor and built-in display.

However the scaling is off on quite a few applications.

From the Screen Display application, the 'Built-in display' is scaled to 200% (this is the default that Ubuntu sets) and works well for the default when I am not connected to a monitor. Then the Dell Inc. 34" screen settings has the scale at 100%.

With these scaling factors my terminal session windows look about correct and so I'm using this as a base.

However there are lots of things that don't seem to match up with my most common applications:

  • Firefox
  • Chromium
  • KeypassXC (this has a QT application UI)
  • Gimp

These are the issues I've hit:

  1. The scaling of the title bars for FF,Chrome and Keypass on the monitor stays based on the in-built display (so scaled to 200% when the other applications are scaled to 100%)
  2. The scaling of the text inside the window remains huge
  3. Adjusting both the in-built and the monitor to 100% still leaves the applications with title bar heights that are scaled to 200% but the text within them is scaled to 100% and the text in the application is still scaled to 200%.

The only way to get things to match up correctly between screen and monitor is to set both to 200% but then everything looks huge on the monitor.

Screenshot 1 (built-in 200%, monitor 100%)

(Current) Best possible but the browser applications are all too big.

enter image description here

Screenshot 2 (built-in 300%, monitor 100%)

This shows the title text being based of the screen scaling and not the monitor scaling

enter image description here

Screenshot 3 (built-in 100%, monitor 100%)

The applications on the monitor still look incorrect and now Gnome applications look tiny on the built-in display.

enter image description here

  • 1
    Currently snap apps do not respect your theme, which includes scaling. Some apps are worse than others. But they are working on it :-)
    – B.Tanner
    Dec 12, 2018 at 8:21
  • @B.Tanner It's Firefox and Chrome too :( I've given up with GNOME and switched to KDE.
    – icc97
    Dec 12, 2018 at 8:29
  • 1
    I also use KDE with a second monitor on an XPS 13 and am loving it, got fed up of fighting gnome. There are still some problems and I have to avoid most snap apps which severely limits the choice of software, but with most you can find a PPA and "sudo apt install" from there if you have to eg. I needed a later version of LibreOffice due to a bug and found the snap version unusable - I could barely see the mouse pointer it was so small - but the PPA version is fine.
    – B.Tanner
    Dec 12, 2018 at 10:41
  • 1
    I should add: I still had to use xrandr.
    – B.Tanner
    Dec 12, 2018 at 10:57
  • 1
    @danger89 It's from a photographer - Tim Flach
    – icc97
    Mar 16, 2019 at 13:32

3 Answers 3


tl;dr: KDE plasma solved my issues but caused others, so I switched to vanilla GNOME 3 leaving the scaling at 200% for both laptop and monitor.

After a month of trying with Wayland and then also regular X I gave up and tried alternative options. I even was willing to accept that scaling would be twice as big on the monitor as long as the menu bars and text would be consistently displayed. However as you can see with the top half of the screenshots in my question the menu bars even on the same screen differ in size and beyond that the close icons don't scale and so the text becomes smaller but the buttons are still just as big.

I first tried Budgie. Where as this is nice, it is just a wrapper on Gnome and so suffers from the same problems - inconsistent menu bar heights and min/max/close icons that don't scale.

KDE Plasma

Then I tried KDE Plasma (recommended via reddit) and this for me works about perfectly - all windows are scaled consistently. The one issue is that by default just through the System Settings > Displays menu you can only scale both the monitor and the in-built screen to the same (same as Gnome X). This means that things are twice as big on the monitor as the desktop, but I can just put terminal windows on the monitor and scale the font down and that's fine.

The KDE Displays menu seems to be a fairly simple wrapper around xrandr - so hopefully they'll extend it to allow independent scaling through the menu. My objective when using Linux is that you can achieve things through menus so that others can use them too. However at least the scaling is consistent and so if I do use xrandr I should be able to get the perfect setup, where as on Gnome the windows were different sizes in the same screen.

Here is a comparison screenshot:

enter image description here

Update: switching to plain GNOME 3

After a couple of months with KDE a couple of annoyances popped up where it doesn't deal well with UHD screens and external monitors.

  1. KDE plasma has a very long loading screen ~10s which got more annoying with each day
  2. The screenshot tool would crash my system and I have to regularly take screenshots
  3. Moving windows between monitors became a problem
  4. There's no bold font in the terminal - silly annoyances but they build up
  5. Other constant niggles with windows

All of this was compared to the almost perfect experience that I have with Fedora + GNOME, plus I guess I'm just comfortable with using GNOME.

So as my current solution I have simply installed the base GNOME 3 (Wayland or not doesn't matter, but I do use Wayland) and I have accepted that the only scaling that handles all the things I care about is the default of scaling 200% on both the laptop and external monitor.

Even with plain GNOME scaling to 100% doesn't work - it just makes the text of the titles smaller rather than shrinking the size of the title bars.

I followed this It's FOSS guide for installing GNOME:

sudo apt install gnome-session

Then I needed a further tweak to switch the login screen back to gdm3:

sudo dpkg-reconfigure sddm 

Now it's the case that actual regular Ubuntu GNOME 3 would also work fine, so it sounds like potentially my best option in the beginning was just to do nothing and accept the large titles on the external monitor **sigh**. But at least my desktop experience is fairly consistent now between my home Fedora Thinkpad laptop and my work Dell Ubuntu laptop.

But I do now have:

  1. Consistent scaling of fonts in the titles
  2. Consistent title bar sizes
  3. Putting my laptop to sleep and then re-awakening it whilst it's connected to an external monitor doesn't move the windows around
  4. Super crisp fonts in the terminal on both the external monitor and laptop (scaling the external monitor to anything other than 200% caused problems)

Now my desktop looks like this:

enter image description here


I have a similar issue with Matebook X Pro (3000x2000) and external 1440p display. Weyland scaling factor not apply to all programs as above.

I also checked other distros and desktop environments, it works somehow on KDE Plasma - I mean scaling was proper on second display - but there was a lot of other issues, for example, some programs not scale in general.

On Ubuntu I also notice touchscreen issue, it works, but it is not the best user experience for me.

I type it with pain, but... for now - it is really hard to write - for now only Windows 10 works fine with this setup. It looks like we have to wait for better Linux support of HiDPI.


After about one week i gave up... Windows 10 is so useless. I am very impressed that OS provided with hardware works so bad (minimum 1 crash/hang per day, about 10Gig RAM used by OS, Candy Crash in menu, preinstalled, in profesional OS!! and many many more bad experiences).

Then I switch back to only right OS - Linux. I'm really sorry that I doubted him.

In some way I workaround this issue. I disabled scaling on both screen (1x scale factor was seted). Then on my HiDPI screen I changed resolution to 1920x1280. I know that is strange resolution but it is because my screen aspect ratio is 3:2. This resolution is apropriate to properly see UI elements and do not casue strange graphical glitches. Everything looks perfect. All programs works like charm. I was afraid when I changed resolution to smaller one then everything will be looking odd. I am impressed how everything works so great and there is no need for scaling.

I setted this weird resolution using xrandr (google is your friend).

For every day use my setup is 3000x2000, 1920x1080, 1920x1080 screens and finaly I can use this potential with power of only right OS.

Currently I am using Ubuntu but this should work on any Linux based OS.

  • I hadn't properly read your answer, but now re-reading I see that we came to the same conclusion (I've added my answer with a screenshot) - KDE Plasma handles the scaling the best. I agree with you on the touch screen, but I practically never use the touch screen. The problem with Gnome that the scaling wasn't consistent within the same screen so even with xrandr you'll never get things perfect. I don't even mind too much that things are too big on the monitor - at least they're consistent.
    – icc97
    Dec 12, 2018 at 8:15
  • I've updated my answer as I've got frustrated with KDE Plasma, so instead I've switched to vanilla GNOME 3 (Wayland works too) and left the scaling at 200% for laptop and monitor. With GNOME I find that the touchscreen is working correctly.
    – icc97
    Jan 29, 2019 at 9:12
  • 1
    After a few weeks (with a few new kernel versions and many updates) with such settings as above, I did not reveal any problems neither with scaling (because it is turned off) nor a touch screen. ...apart from my own destructive activity, the system is fully functional and looks perfect. Maybe some day i will figure out how to get fingerprint to work. Feb 13, 2019 at 8:31

Things have gotten much better in KDE Plasma since the question was asked. My new XPS-15 with a 4K internal screen and an external 28" monitor works reasonably in a Plasma Wayland session in kubuntu 20.04 if I set the internal screen to 2x scaling and the external one to 1x.

Native Plasma apps are perfectly scaled on both screens. As far as I can tell, so are QT apps and probably any native Wayland apps.

What doesn't work perfectly is legacy X11 apps running through XWayland on the internal screen. All the window decorations are good and the content is caled to the correct size but is clearly rendered at a low resolution and then scaled to the screen as a bitmap so it becomes fuzzy. Unfortunately that includes all the web browsers and my python IDE. So they get mostly dragged to the external screen and the internal screen is used for (gorgeous) terminal windows, file managers and simple editors.

Still, this is enormously better than the previously accepted answer of setting the internal screen to half its native resolution.

External screen over internal screen

So my screen now looks like the above screen-shot. What it doesn't show is that the browser window in the bottom-left is a bit fuzzy compared to the super crisp terminal window in the bottom-right.

  • Could you add a screenshot of your monitor and laptop combined? - it's useful to see the scaling on the different screens
    – icc97
    May 14, 2020 at 11:12
  • Oh, I'd love to. But because stackoverflow and all its spawn are brain-dead I need to have at least 10 reputation to do that so they won't let me. But all windows have exactly the right relative size. The only issue is that non-wayland windows on the 4K internal display look fuzzy compared to the super crisp wayland windows on the same screen.
    – logi
    May 15, 2020 at 13:01
  • Perhaps this image link will work? They transcoded the PNG to JPG so everything looks a lot more blurry than it does in real life.
    – logi
    May 15, 2020 at 13:06
  • ah, lol. I've upvoted your comment, so you should have 10 reputation now. Plus I'll add your screenshot anyway as I've got permission to do so.
    – icc97
    May 18, 2020 at 9:22
  • 1
    Your edit then got rejected and re-approved and re-rejected and I finally approved it and edited it with a bit of descriptive text. This is the sort of thing that leads to my previously stated opinion of SO and derived systems.
    – logi
    May 23, 2020 at 15:00

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