Windows phone 8.1 - select field shows keyboard before picker/list appears

I have a bog standard select field on a form, in Android and iOS when you tap the select field the list/picker appears. On my Windows Phone 8.1 device when you tap the select field the keyboard popups up and down before the list/picker appears.

Help......

I'd really like this to work as we're trialling Sencha Toucha with a view to it becoming our mobile dev platform instead of Xamarin. Everything was going well until we tried WP8.1 where we've encountered numerous issues.

Thanks.

Windows phone 8.1 - select field shows keyboard before picker/list appears