I am using Raspbian Jessie Lite and I want to display a website in iceweasel kiosk mode.
To realise this I created an `.xsession` file which gets executed when booting.

When the website displayes a black border is shown, too.

In the */boot/config.txt* I uncommented the `disable_overscan=1` part. But it gets ignored.

If I try to config the `overscan_left` `overscan_right` `...` part in negative values it gets ignored, too.

In the picture you can see the problem better.
[![enter image description here](https://i.stack.imgur.com/lyr2B.jpg)](https://i.stack.imgur.com/lyr2B.jpg)

Why are my settings in the config file ignored? And how can I fix this?