Created attachment 132250 [details]
Video recording showing the issue

SUMMARY

Mouse selection in the desktop has a considerable latency compared to other animations in the Plasma environment, such as mouse selection in Dolphin. See the attached video for a comparison.

This is clearly not a critical bug, but it makes Plasma feel heavyweight. So it may be worth investigating a bit.

STEPS TO REPRODUCE

1. Create and resize a rectangular selection in the desktop by dragging the mouse rapidly.
2. Create and resize a rectangular selection in a Dolphin window by dragging the mouse rapidly.

OBSERVED RESULT

The rectangular selection on the Desktop lags considerably behind the cursor.

EXPECTED RESULT

The delay between selection and cursor should not be easily noticeable, as in Dolphin.

SOFTWARE/OS VERSIONS

Operating System: Arch Linux
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.74.0
Qt Version: 5.15.1
Kernel Version: 5.8.14-arch1-1
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-6200U CPU @ 2.30GHz
Graphics Processor: Mesa Intel® HD Graphics 520

ADDITIONAL INFORMATION

Thank you.