Bug 82558 – Toggling <input type="range"> readonly or disabled state while active breaks all click events

• Component: Forms
• Status: RESOLVED FIXED

[Joseph Pecoraro]

Created attachment 134458 [details]
[REDUCTION] Test Case

See attached reduction.

If a user is actively dragging a slider and it toggles its readonly / disabled state
buttons, other sliders, etc. stop working.

[Joseph Pecoraro]

My guess is that we miss a call to SliderThumbElement::stopDragging at some point
to clear the global capturing mouse events node:

    frame->eventHandler()->setCapturingMouseEventsNode(0);

[Joseph Pecoraro]

Yep, calling stopDragging() when fixes the issue. There are a couple different
ways to fix this. I'm going to put up a few patches and let you know which
one I recommend. I'm in the process of doing a build.

[Joseph Pecoraro]

Created attachment 134472 [details]
[PATCH] Proposed Fix 1: Stop Dragging when readonly / disabled state toggles

[Joseph Pecoraro]

Created attachment 134474 [details]
[PATCH] Proposed Fix 2: Stop Dragging in the early bail

[WebKit Review Bot]

Attachment 134472 [details] did not pass style-queue:

Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebCore/ChangeLog', u'Source/WebCor..." exit_code: 1
Source/WebCore/ChangeLog:10:  You should remove the 'No new tests' and either add and list tests, or explain why no new tests were possible.  [changelog/nonewtests] [5]
Total errors found: 1 in 5 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Kent Tamura]

I like Proposed Fix 2 because of simplicity.

[Joseph Pecoraro]

(In reply to comment #6)
> I like Proposed Fix 2 because of simplicity.

I wonder if we should take both.

  • Proposed Fix 1
    - this would stop an active drag if the input is changed to disabled and back quickly.
  • Proposed Fix 2
    - any early return should logically stop the drag.

Should I spend time trying to make a test for this?

[Joseph Pecoraro]

I see there is: LayoutTests/fast/forms/range/range-drag.html
I'll see if I can make a test for this.

[Joseph Pecoraro]

Created attachment 134483 [details]
[PATCH] Fix with test

Now with test!

The question now is if we want the following scenario to work.

    1. User starts dragging
    2. <input> becomes disabled
    3. <input> becomes enabled
    4. User continues dragging.

The test does not really test this scenario, it only really tests that mouse events
don't stop working when a toggle during an active drag happens.

[Joseph Pecoraro]

Created attachment 134484 [details]
[TEXT] Expected Results Before Patch

This is to show that the test does change from before and after. This is the before, note that the attempt to drag the second slider fails.

[Kent Tamura]

Comment on attachment 134483 [details]
[PATCH] Fix with test

ok

[WebKit Review Bot]

Comment on attachment 134483 [details]
[PATCH] Fix with test

Clearing flags on attachment: 134483

Committed r112547: <http://trac.webkit.org/changeset/112547>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.