[Bug]: Conflicting interactions of middle mouse button on PDFs when autoscrolling

[realooffyy]

Version

Version 0.12.4.1 (Official Build, Chromium 148.0.7778.178) appimage (64-bit)

Have you tested that this is not an upstream issue or an issue with your configuration?

• I have tried reproducing this issue in Chrome and it could not be reproduced there
• I have tried reproducing this issue in ungoogled-chromium and it could not be reproduced there
• I have tried reproducing this issue in Helium with a new and empty profile using --user-data-dir command line argument and it could not be reproduced there

Description

When attempting to move in a PDF using the middle mouse button and with the middle-click-autoscroll flag enabled, the PDF moves in opposite directions.

How to Reproduce?

1. Enable helium://flags/#middle-click-autoscroll.
2. Hold down the middle mouse button and move the mouse down.
3. The PDF pans up, since you're grabbing it with the middle mouse, and the autoscroll starts to scroll down the PDF simultaneously.

Same happens in other directions.

Actual behavior

The PDF pans in the opposite direction to the autoscroll, so the PDF moves unpredictably.

Expected behavior

Either panning or autoscrolling should be prioritised, perhaps with a toggle.

Additional context

Could not recreate in Chrome or ungoogled-chromium since neither have an autoscrolling option/flag (afaik)