Horizontal Navigation in a big grid not working

[Cyberdada]

If you have a big grid (+ 40 rows) then if you are placed in say col #38 and press right arrow, you end up in col #1, instead of col #39 (which would be the expected behaviour)
(the col you are in when pressing the left arrow has to be like one or two columns right of the last visible column for this to happen. )