[REGRESSION] touchpad behavior broken: left button press delayed if finger is on touchpad

[Teo]

This is a REGRESSION. This used to work fine. I don't know when exactly it broke.

Steps to reproduce: Test 1 and Test 2 should both behave the same as test 2, but test 1 gives nonsense and dangerous results.

--Test 1--
- place finger 1 on the touchpad
- move the finger around while keeping it in contact with the touchpad => the mouse cursor moves around as expected
- with another finger 2, press the left button and hold it, while finger 1 is still on the touchpad, at point "A"
- (*) move finger 1 around on the touchpad to some other point B, then stop moving it
- move finger 1 around again, to point C
- only then, release the left button

-- Test 2 --
- place finger 1 on the touchpad
- move the finger around as in test 1
- take finger 1 away from the touchpad, leaving the cursor at point A
- with another finger 2, press the left button and hold it
- place finger 1 on the touchpad again and move it around, then stop at point B.
- Move finger 1 a bit more, to point C
- release the left button

Expected result:
OBVIOUSLY, in both cases, the behavior should be the same. A left button press should be registered at point A, then a drag movement to B and then C, and then a button release. If, for example, at point A you hit something draggable, the result is that you drag it and drop to point C

Observed result:
Test 2 behaves as expected
However, in test 1, nothing happens when you actually press the button. Instead, a button press is registered when finger 1 pauses at point B. That is, everything behaves as if you had pressed the mouse button at a completely different place and time than you did. The result is dragging from point B to point C.

The consequences can be disastrous. This can lead to data loss, because a click may be registered on a button that delete things, or the drag-and-move operation that is executed (completely unrelated to the real action of the user) may be that of moving an object to a place where you're not supposed to move it (e.g. moving a file to the trash or whatever).

This can literally result in formatting your hard drive.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.2.2+14.04.20140714-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.13.0-37.64-generic 3.13.11.7
Uname: Linux 3.13.0-37-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CurrentDesktop: Unity
Date: Sun Oct 12 17:17:03 2014
InstallationDate: Installed on 2013-10-11 (365 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
SourcePackage: unity
UpgradeStatus: Upgraded to trusty on 2014-05-24 (140 days ago)

[Teo (teo1978)]

For god's sake, the impact of this is huge.

Because of this bugs I have moved messages in Thunderbird from a random folder to another, which is equivalent to loosing them (impossible to figure out what I moved where), moved entire folders; the same with files in Nautilus. I have devastated Android Studio projects.
All because a mouse press even is registered at a "random" point in space and time (it actually follows a strict logic as described in the report, but that is unrelated with the real behavior of the hand on the touchpad).
This is like having a cat walking on your keyboard. Well, actually it's worse; the probability of doing serious damages is higher.

This needs urgen attention.

[Teo (teo1978)]

Oh, I forgot, among the disasters that happened to me because of this bug, I also accidentally sent emails that I hadn't finished writing.

[Teo (teo1978)]

There seems to be also another (dangerous and annoying) glitch of which I can't find the exact pattern.
Often I click with the touchpad button and TWO consecutive clicks are registered (not necessarily a double click).

[J (lopata199)]

Maybe simpler test is run one of the map services in browser (i.e. http://maps.google.com). You are not able to move the map while your finger keeps touch with a touchpad. Very annoying.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[teo1978 (teo8976)]

I thought this had been fixed because i stopped observing it, but now it's happening again.

So, either this was fixed and then broken again (unlikely), or more likely this is intermittent, perhaps triggered by some particular event.

This should have very high priority, as it renders any laptop completely unusable unless you have an external mouse.