Aspire R7 572G touchscreen is unstable when connected to an external monitor, via minDP/HDMI

saleall

Basically the problem is that, the touchscreen function and stylus input become unstable when the notebook is connected to external monitor via miniDP or HDMI. I've done every thing possible and this is last things I'm doing to fix this.

I own Acer Aspire R7 572G.
I use it usually for school. so i use Microsoft OneNote a lot.
The notebook comes with stylus, and also touch screen. 
It does not have a discrete GPU so it uses the built-in  Intel HD Graphics 4400.
Every and all the drivers including windows update are up to date, (certain).
Running windows 8.1 pro.

Everything thing works fine
except when i connect the notebook to my DELL 2713hm via DisplayPort,
Touch screen and stylus don't working well, and when i try to write using stylus on OneNote, it does not ignore touch like it usually do when writing with stylus. I usually completely disable touch in the Device manager so only the stylus works, but when connected to the external monitor, touch screen still registers touch even if  it's disabled.

Things that i did to diagnose this (while connected to the external monitor in extended desktop mode);
- Disabled touch completely in device manager, touch screen still registers touch in a very buggy(stuttering way)
-Disabled only the stylus in device manager; Touch screen works fine and is fully functioning and no problem what so ever. and the stylus don't work ofcaurse. 
-Tried to calibrate touch screen, identify the notebook screen as my touchscreen, tried to switch my default desktop to external monitor and back, reformated my entire notebook, updated to the latest windows update, tried to disable bunch of other devices in device manager/registry/Services,  still the problem remained, and touch screen cant be completely disabled at all.
-Installed windows 7 Ultimate on the notebook, still exactly same problem, 
-Used HDMI instead, still the problem remains.

But if i disconnect external monitor and restart the notebook then everything gets back to normal and touch/stylus work exactly as it should. Therefore i have to disconnect the monitor when using Stylus and OneNote every time. 

So i have no idea what the problem is, tho it looks to me that it's a driver issue, and why the touch screen cant be disabled completely in device manager, while the notebook is connected to an external monitor (Tried another monitor too).
I appreciate any kind of help regarding this issue, and i need this to work, as i use my notebook for study, and need more desktop space, i will have to have this just working.

Is there any alternative driver for chipset?
Just what should i do to fix this? 
PC still under waranty. should i return it?
For GPU intel HD 4400 i use the intel driver updater and have installed the latest drier v15(official one is older)
thanks in advance.