Arrangement zoom doesn't work

[benmusic87]

Hi,

I have been working on a project and for some bizarre reason the arrangement zoom at the top of the playlist window has gone wrong.
It is either fully zoomed in or zooms all the way out way beyond the end of any clips.

I have attached a screen video so you can see whats wrong.

It is driving me mad as it is completely ruining my work flow

Any help would be much appreciated

Cheers

Ben