Bug 20872 - PREVENT MOUSE EVENT flag should be per pointer type
Summary: PREVENT MOUSE EVENT flag should be per pointer type
Alias: None
Product: PointerEventsWG
Classification: Unclassified
Component: Pointer Events specification (show other bugs)
Version: unspecified
Hardware: PC Windows NT
: P2 normal
Target Milestone: ---
Assignee: Jacob Rossi [MSFT]
QA Contact: Pointer Events Bugzilla list
Depends on:
Reported: 2013-02-05 04:13 UTC by Jacob Rossi [MSFT]
Modified: 2013-02-07 02:17 UTC (History)
1 user (show)

See Also:


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Description Jacob Rossi [MSFT] 2013-02-05 04:13:32 UTC
> Upon re-reading the current draft, I have a few questions.
> 1. At any point in time, how many pointers can simultaneously have isPrimary
set to true? The way I read it, there could be up to three, one for a mouse
device, one for a touch input, and one for a pen input, if the underlying
platform supports all three input types simultaneously. Is that correct?

Correct. Generally, users don't mix input simultaneously. In IE10, multiple primary pointers effectively "fight" for a mouse cursor (e.g. you'll see mousemove events firing back and forth between the two locations).

> 2. If my understanding in #1 is correct, then in "8.1 Mapping for devices
that support hover", there should be *three* different PREVENT MOUSE EVENT
flags, one for each input type. Otherwise, cancelling the pointerdown event
of the primary touch input would inadvertently disable the compatibility
mouse events for subsequent events from the primary mouse and pen inputs as

Though I think I'll update this to say "set the PREVENT MOUSE EVENT flag for this pointer type" and "if the PREVENT MOUSE EVENT flag is set for this pointer type." That way the principle applies if new device types are added.