Sometimes, the cursor moves itself to the edges of the screen. I have to lift the mouse and put it down and then it works again. I have tried cleaning the sensor at the bottom; the only problem left that I can think of is the mouse mat (an unnamed; cheap one and rather small).
Could the mat causes this kind of problem? Is an official Razer mat required in order to use this mouse?
In the past, the Razer Lachesis had a "jumping" problem which may or may not apply to the Death Adder.
A Razer mat is not required, but recommended. The Death Adder is an Optical Mouse (as opposed to Laser) so you'll want a mat that's geared toward optical mice.
From the Razer Lachesis FAQ:
What type of mouse pad will work best with the Razer Lachesis?
We have found the Razer Lachesis to perform at its best with a hard mouse pad surface. We recommend the Razer Destructor, although any quality hard surface mouse pad will work as well.
