X220 tablet cursor jumping in laptop mode.

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Just picked up an x220 tablet & noticed the cursor can jump around especially when playing videos in laptop mode.
It is not a massive issue & after a quick google search have found quite a few references to this issue.
Some people mention it may be a fault on the motherboard ( i wont be replacing that as too expensive & not capable of doing so myself).
I was just wondering if anyone had similar issues & found other possible fixes?
edit: Its a finger touch model if this makes a difference?

Thanks

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Just a quick update on this. Now i have obtained a battery it only seems to do it while running on mains.
Also seen ref to similar issues with other makes of laptops when using a generic/copy psu. However im using a genuine 90w. Could be some electrical problem? There is some plastic damage to the chassis & a couple of sizeable cracks so maybe interference is getting in that way? Was going to fill them in with sugru as kindly suggested by RBS but not done yet.
Only because noticed a couple of suggestions online mentioned a possible fix could be grounding the laptop with kitchen foil & leaving a bit exposed?
Anybody tried that?