Created attachment 174543 [details]
There is a gap along the whole right edge of the window. Zoom in to see it.

SUMMARY
When using fractional scaling, there is a gap between the right side of Dolphin and the window border. This is probably a Qt or Frameworks bug and not a bug within Dolphin itself.

STEPS TO REPRODUCE
1. Enable fractional scaling in a Wayland session. I am using 1920x1080@125%.
2. Open Dolphin.

OBSERVED RESULT
There is a gap where there shouldn't be. See attached screenshots.

EXPECTED RESULT
No gap, just like other KDE applications.

SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux 2.15
KDE Plasma Version: 6.2.0
KDE Frameworks Version: 6.6.0
Qt Version: 6.8.0
Kernel Version: 6.11.2-20R5-sched-ext (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i5-10310U CPU @ 1.70GHz
Memory: 7.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics

ADDITIONAL INFORMATION
This bug was present for me on Plasma 6.1.5/Qt 6.7.3. It did not go away after upgrading to Plasma 6.2.0/Qt 6.8.0.