Can't use extended DSS key labels on a T48S

[FredyWenger]

Hi
I have bought a brand new T48S (touch screen) (I use it with a 3cx PBX).
Updated to the latest supported FW from 3cx (66.83.0.20).
If I change the the Label Length to “extended” under Dsskey (in the web client) this does not work and make the device unusable for us.
Further, it seems that also some other settings over the web client don't have effects…

How can I set the Label Length to “extended”?
I don't have found such an option directly on the device.
Also the display is very bad (blurry) if I look at the device from an normal angle...

Update:
I am able to set the Label Length to "extended", but the text then is showed in two lines - what I want is to enhance the length of the while element (box). I now have short boxes on the left and the right side on the display (text showed in two lines) and a lot of unused space in the middle of the screen looks very ugly!
So.. new question: How can I extend the length of the boxes?

I also have a T46S (without touch screen):

Here, the Lable Length setting over the web client works and also the display is way better with the normal view angle!