Can't change menu order

Hiya,

Sorry, me again. I'm still working on my site

www.dancefilm.co.uk/testsite

On the Main Menu, I can't seem to move What's On 's position. Every other menu item is movable but it just won't let me change its position?

Help! I essentially need it to be next to Home but it just won't let me move it from Position 6.

Thank you!