Launcher - unable to reveal Launcher under autohide after using the touch screen

Attach kern.log, syslog, Xorg.0.log, dmesg
Nothing has changes in these logs after the issue occurs.
Nothing has been observed in .xsession-errors, too

Private bug #1220990 is a duplicate of this one.

I haven't seen a touchscreen on consumer hardware that supports only a single touch in years. Unity is not designed for such ancient technology.

The gesture to reveal the Launcher on a touchscreen is a 4-finger horizontal drag. The Dash can be revealed with a 4-finger tap. This functionality has been available in Ubuntu since 11.10.

@Stephen,

Many thanks for your reply.
Sorry my description maybe a bit mis-leading, this is not a single-touch bug, but a possible Unity bug that touchpad cannot reveal launcher if a left-click event happens via touch-screen.

Some more information for your reference:
1. This does not happen under Unity2D but only Unity3D
2. Windows hotkey still works, so the launcher can be called via hotkey
3. When issue occurs, unity --replace or compiz --replace cannot recover it. I only found restart lightdm (restart X) can recover the issue
4. No error occurs from
$export UNITY_LOG_SEVERITY="=DEBUG;nux=DEBUG"
$unity --replace
5. If I touch the screen before setting launcher to auso-hide mode, touchpad or external mouse still cannot reveal the launcher after autohide is selected.

Extra information which may not relate to this issue directly:
The position of touchpad pointer and touch screen pointer do not sync with each other. For example, if I move the pointer to place A via touchpad, then touch place B on the screen, then tried to move pointer via touchpad, the pointer appears at place A instead of place B.

We are using Precise 12.04.2 with
unity 5.20.0-0ubuntu2
unity-2d 5.14.0-0ubuntu1
compiz 1:0.9.7.12-0ubuntu2
and kernel 3.5.0-40-generic

Tammy,

Can you check if you can only reproduce it when you reveal the launcher with alt-f1?

Thanks,
Ara.

@Ara,

No, I didn't found alt-f1 has a relationship with this bug.
Before I touch the screen, everything is normal, alt-f1 can be used, moving cursor to the left side can reveal the launcher.
After I touch the screen, alt-f1 can still be used to reveal the launcher. However, moving cursor to the left side no longer works.
This is consistent to what we found at the beginning, the launcher can reveal via hotkeys but not via touchpad.

I had this issues just after hiding the launcher, but after a restart it seems to work.

BTW: Can anyone reveal the launcher with a touchscreen? Using edges for showing the desktop etc. with compiz works, but no chance with the launcher. The sensibility behavior should have an option that allows to reveal the launcher by just moving in the edge without pulling against it.

I believe this may be a known bug in XInput in which touch-release events are not being sent. WIll dig in to it.

I can not reproduce this in trusty daily build today. I think it already fixed in trusty.

Marking it as Fix released in the OEM priority project