I know that this is an old thread, but this was the second result on google search when trying to find the horizontal scroll solution. I have a lot of grids which look perfectly fine on desktops and tablets, but when you look at them on a mobile phone they go over the right edge like on Misahael's picture.
Anyway, this was my general solution:
.k-grid {
overflow-x: auto;
}
It would be even better to somehow pin the right-most column (with buttons), but for now/me this will do.