201496 2019-09-05 00:08:04 -0700 MouseEvent.button should be 0 for mousemove events 2026-01-12 09:09:42 -0800 1 1 1 Unclassified WebKit DOM WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=198679 InRadar P2 Normal --- 1 fujii webkit-unassigned ap cdumez graouts pvollan webkit-bug-importer oldest_to_newest 1568034 0 fujii 2019-09-05 00:08:04 -0700 MouseEvent.button should be 0 for mousemove events Spec: https://www.w3.org/TR/uievents/#dom-mouseevent-button > The value of button is not updated for events not caused by the > depression/release of a mouse button. In these scenarios, take > care not to interpret the value 0 as the left button, but rather > as the un-initialized value. test case 1: attachment 377952 test case 2: https://jsfiddle.net/fujihiro/vy7hkpLw/10/embedded/result Firefox and Chrome set it 0 for mousemove events. 1568913 1 ap 2019-09-07 12:40:15 -0700 This seems to work in Safari. Is this a Windows port bug report? 1569057 2 fujii 2019-09-08 20:55:19 -0700 This is a test procedure: 1. Open attachment 377952 2. Hold the mouse middle button pressing 3. Move the mouse button should be 0, but 1. I tested with Safari Technology Preview 91 and Safari 12.1.2. 1569123 3 webkit-bug-importer 2019-09-09 06:34:47 -0700 <rdar://problem/55180368>