WebPlus X6: Help with Contact form TAB ORDER

You would think, after the years I have been a WP user I would be able to adjust a simple thing like Tab Order.

On this occasion it is driving me mad. I know exactly what to do but WP is stopping me complete the operation. I can get the 1st 3 tabs ordered then as soon as I try to select the 4th tab I get thrown out of the form.

I have tried zooming in to ensure I am hitting the tab, no difference.

Could his be a Win 8 bug?

If anyone can help me with this please post here and I will send you the wpp file on PM.

Thanks Greg