Closed Bug 1607258 Opened 4 years ago Closed 4 years ago

Using scroll bar with mouse highlights text in webpage when using apz.allow_zooming=True


(Core :: Panning and Zooming, defect)

71 Branch
Not set





(Reporter: ke8fgb, Unassigned)



(1 file)

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0
Firefox for Android

Steps to reproduce:

I turned on the config option apz.allow_zooming because I have a touchscreen device. With this option turned on, trying to scroll by clicking and dragging the scroll bar works, but highlights text in the webpage as well.


  • The issue has happened to me many times across a wide variety of websites, so the bug is not website-dependent.
  • The bug is reproducible in a regular window and a private browsing window.
  • The bug is reproducible (first noticed) in my standard Firefox profile and a brand-new profile.
  • The issue exists in both Firefox Stable (71.0) and Nightly (73.0a1, 20200106092427).
  • Changing apz.allow_zooming to False without changing anything else does not trigger the issue (no restart of Firefox is needed after changing that option).

Actual results:

When attempting to scroll using the mouse with the scroll bar with apz.allow_zooming=True, the scroll bar works but highlights text inside the webpage in addition to scrolling. Because the text selection constantly changes as you scroll down (because you're clicking and dragging), this produces buggy behavior as a side effect of the scrolling and the text highlighting interfering.

Expected results:

When using the mouse on the scroll bar to scroll down, text on the webpage area should not be highlighted.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Component: Untriaged → Panning and Zooming
Product: Firefox → Core

It says "Firefox for Android" in the report, but I selected the option for issue with phone/tablet because it's a touchscreen-related issue. Clearly that didn't do what I thought it would; this issue is in fact only for Firefox on Windows 10. My apologies for any confusion that may cause.

Thanks! This is a known issue with desktop zooming which will be fixed in bug 1556556.

Closed: 4 years ago
Resolution: --- → DUPLICATE

Aha, alright. I saw #1556556 when I searched but didn't see from the title that that was the same bug, and none of the duplicate bugs marked in that thread showed up either.

I'll go vote up that one, thanks!

(In reply to ntoskrnl4 from comment #4)

I'll go vote up that one, thanks!

There is no need to vote, it's being actively worked on. It's just turning out to be a difficult problem technically and therefore taking longer than anticipated.

Ehm..okay...I'll take it back then I guess? Just wanted to help

It's all good! I was just explaining why movement on that bug has been slow :)

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