I'm quite new with LINUX and having strong issues with the following touchpad:
Hardware: LENOVO ThinkPad X240 http://www.linlap.com/lenovo_thinkpad_x240
Operating System: kUBUNTU 14.04

My Problem: The touchpad behaves strange, the computer is actually unusable, f.e.:

* The mouse pointer is jumping, f.e. clicking the X to close a window, needs lots of trials, as the pointer doesn't stay on the X.
* Starters on the desktop are executed, while the mouse pointer is crossing the icon.
* Marking a certain text character on a sheet in LO-Impress usually move the page up or down or moves the text frame within the page.

Trials for improvement done in the past (all without success):

* All regular Updates were done.
* KDE: Updated to 4.14.2.
* File /etc/default/grub added <acpi_osi=Linux> into line <GRUB_CMDLINE_LINUX_DEFAULT>, e.g. now <GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"> and <sudo update-grub> after that.
* File 50-synaptics.conf: I've found several proposals (f.e. https://mydevelopedworld.wordpress.com/ ... ntu-13-10/ and others) to modify this file, without real success. Obviously no changes in the behaviour of the system with whatever setting.
* Also tried several operating systems (trial DVD without installation) and found, that this behaviour is obviously worst with KDE / KCM-Touchpad 0.99, f.e.:

* kUBUNTU 14.04 (as above),
* MINT 17 KDE,
* MAGEIA 4 with KDE 4.11.4.
* With UBUNTU 14.04 or MINT 17 Cinnamon the hardware behaves much better (no jumping windows, no software atarts by crossing a starter).

Finally tried ((Trial DVD without installation) kUBUNTU 15.04 (KDE-Plasma 5.1.95, Qt 5.3.2, Kernel 3.18.0-9, 64 bit) and this behaves nearly perfect. No jumping windows, mouse clicks can be exectuted by tapping the pad, while with the above version a mechanial press (hearable) had to be done.
I copied the 50-synaptics.conf from 15.04 to the kUBUNTU 14 system (as above) and it behaves odd as before. So obviously not the 50-synaptics.conf is relevant for the behaviour.

How can I improve the 14.04 system? Is something missing or wrong in setup? How can I make the 50-synaptics.conf effective?
Thank you.

the kcm-touchpad package is the control module (configuration tool) not the actual driver, the driver I think is the xserver-xorg-input-synaptics package so try reinstalling it and see if other versions are available to try

Thank you very much for your answer and the proposal, sounds really promising to me.
I found the following versions for Driver xserver-xorg-input-synaptics (using dpkg -l):

* installed PC kUBUNTU 14-04 / KDE 4.14.2: 1.7.4-0ubuntu1
* Trial DVD kUBUNTU 15-04: 1.8.1-1ubuntu1

So I would like to replace the driver to 1.8.1-1 and found pages like this, where the 1.8.1 listed. Unfortunately my knowledge is not sufficient for the installation procedure and I don't know how to proceed. Already tried to get advise for this but no answer yet. I'll come back to you as soon as I've learned the procedure for installation.

did you try reinstalling the 1.7.4 package, sometime reinstalling does fix issues

the 1.8.1 drivers appears to be available in the Trusty Updates ppa, package xserver-xorg-input-synaptics-lts-utopic so you might be able to add the updates ppa and get it. how to do that would be on the Kubuntu site and any questions regarding its use would be best asked there. As I don't use Kubuntu I'm just speculating

1.8.1 is also available in 14.10 if you were inclined to update

Just a short update:
I did not really deinstall / reinstall the 1.7.4, but a dpkg-reconfigure xserver-xorg-input-synaptics has been executed, without any success.

Actually I'm updating to kUBUNTU 14.10 in order to avoid any conflict with the 1.8.1-driver.
This touchpad is going to drive me crazy!
Thanks for your advice, I'll come back as soon new software is running.

The system is running kUBUNTU 14.10 now and the driver is xserver-xorg-input-synaptics 1.8.1-1.
The touchpad behaves quite fine and some improvements will be checked out with different settings in 50-synaptics.conf.
Thanks for your time and advice. For the first time, it made my new hardware usable!
Best Regards
Michael