549669 - Pressing control key in the middle of a scroll changes font size.

Status: RESOLVED DUPLICATE of bug 574663

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Blake Winton (:bwinton) (:☕️)]

STR:
Open a page in Firefox
Start to scroll with magic mouse, with momentum turned on.
While it is scrolling with momentum, without your finger on the mouse, press and hold the ctrl key

Observed behaviour:
The page starts scrolling, then stops and the text changes size.

Expected behaviour:
The page continues scrolling.


(The page I used was https://wiki.mozilla.org/Thunderbird:Thunderbird3.1:Driving_Scratchpad, but it seems like any page would do.)

Comment 1

[:Gavin Sharp [email: [e-mail]]]

I imagine this won't be easy to fix if the "momentum" is handled entirely on the mouse driver side (i.e. we're just receiving multiple distinct scroll events).

Comment 2

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

There are multiple points in time when we should "stop" any currently existing momentum, such as when closing or switching tabs. Right now if you scroll on one page and then quickly switch tabs using the keyboard things look very strange.

Does the OS expose any APIs for clamping any currently existing momentum to 0?

Basically any time a key is pressed it would be nice to clamp. Of course, you could definitely argue that the OS should do that.

Comment 3

[Markus Stange [:mstange]]

The issue that this bug was originally filed about was fixed in bug 574663, so I'm marking this as a duplicate.

(In reply to comment #2)
> There are multiple points in time when we should "stop" any currently existing
> momentum, such as when closing or switching tabs.

That's bug 605751.

> Does the OS expose any APIs for clamping any currently existing momentum to 0?

No, but we can do the clamping ourselves by ignoring subsequent momentum scroll events.