1257813 - Click event happens on old element after I release mouse (mouseup) over another element on http://www.thedailybeast.com

Status: RESOLVED DUPLICATE of bug 1187591

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

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 48, 32bit, ID 20160317030235
STR:
1. Open
   http://www.thedailybeast.com/articles/2016/01/10/are-russians-and-ukrainians-the-same-people.html
2. Scroll a bit down so that "READ THIS. list" became fully visible
3. Make sure that the 1st item in that list is only partially grayed out.
4. Hover mouse over the text in the 2nd item in that list
5. Hold left mouse button
6. Move mouse to the left, to the article's text (move it away from the 2nd item)
7. Release left mouse button

AR:  The 2nd item is clicked. If I set breakpoint on 'click' event, it fires with
     e.explicitOriginalTarget == the 2nd item.
     If I add attribute [onclick="console.log('fake click')"] to the 2nd item (<a> element),
     then I see that message in console.

ER:  No click, because I moved mouse away. Just like in GoogleChrome browser

Note:
 A friend of mine (who is "regular joe" Mozilla is aiming to) was very disappointed when I showed
 him several cases when Firefox fails to do this trick - "mousedown-drag-mouseup to cancel click" 
 He's using GoogleChrome btw

Comment 1

[Andrew Overholt [:overholt]]

Olli, WDYT?

Comment 2

[Dennis Schubert [:denschub]]

Same story as in bug 1257816. there's a `overflow: hidden;` on `.sidebar .rtl-list .rtl-item h3, .sidebar .rtl-list .rtl-item h4`. Without that, dragging out does not fire the click event. This is tracked in bug 1187591.