(URGENT) Disabling a "real-time test mode"

Hi all,

I have a Hero H5500 (also known as ZOPO ZP100 but with a different ROM inside), it's a MT6575 phone.
Last night I fell asleep while watching a Youtube video (yes, that happens sometimes ^^) with the phone in my hand...
But when I woke up this morning, a bad surprise was waiting me :
I guess I involuntarily made a shortcut which activated this kind of "real-time test mode" on my phone :
[D*** it !!! I can't post the screenshot because of spam preventing :( It must be THE thing you need the most to solve my problem !!!]
the blue lines are what I do with the touch screen (which reveals another big problem I have, when my phone is plugged in, I have a lot of touch screen glitches : my finger did just do the "U" in the middle).
some infos (like the position I touch for example) are displayed in this line on the top and there is a real time display of applications and services used by the phone with some indicators of CPU used like a task manager...

Is it an Android native feature or a MT65XX firmware feature ?
How to disable it ?

Thank you by advance !