Fractional scaling display error Ubuntu 20.04 and OBS 27.0.1

[richtertoralf]

Operating System Info

Ubuntu 20.04

Other OS

No response

OBS Studio Version

27.0.1

OBS Studio Version (Other)

No response

OBS Studio Log URL

not available

OBS Studio Crash Log URL

No response

Expected Behavior

normal start and window as always

Current Behavior

Steps to Reproduce

1. I use one 4K monitor and two FullHD monitors.

2. Select "Fractional scaling" in the settings for display devices. Set 150%.
   

3. Launch OBS Studio
   -> Missing the line with File, Edit, Profile, ....
   -> The lower section is double.

See screenshot!

Anything else we should know?

I have tested different variants of FFmpeg and also installed OBS-Studio several times. Whenever I select "Fractional Scaling" and set e.g. 150%, OBS shows this strange behavior.
I am using Ubunte 20.04 LTS minimal version with X11 without any changes. Ubuntu I have freshly installed. Except for ffmpeg and OBS I have no other programs installed.

[kkartaltepe]

Fractional scaling was disabled on linux because qt was broken.