Why ListPicker always showing in FullscreenOnly mode - windows-phone-8

Question

I am using a ListPicker and it is always showing in FullscreenOnly mode even if i change the ExpansionMode to ExpansionAllowed.
But in other page the same code is working properly.
Why is this strange behaviour happening?

Answer 1

(Assuming this is the Windows Phone Toolkit ListPicker)
If your list is longer than 5 items then it will open in FullScreenMode. It isn't possible to change this threshold value.
So, this one will expand:
<toolkit:ListPicker Header="Background">
<sys:String>dark</sys:String>
<sys:String>light</sys:String>
<sys:String>dazzle</sys:String>
<sys:String>4</sys:String>
<sys:String>5</sys:String>
</toolkit:ListPicker>
This one will always be full screen:
<toolkit:ListPicker Header="Background">
<sys:String>dark</sys:String>
<sys:String>light</sys:String>
<sys:String>dazzle</sys:String>
<sys:String>4</sys:String>
<sys:String>5</sys:String>
<sys:String>6</sys:String>
</toolkit:ListPicker>

Answer 2

It is possible to expand more then 5 elements. You must set ItemCountThreshold.
I set it in view model in method where I set collection's items.
Collection = new ObservableCollection<Item>
{
new Item();
new Item();
new Item();
new Item();
new Item();
new Item();
}
CollectionItemsCount = Collection.Count;
And binding in xaml:
<toolkit:ListPicker ExpansionMode="ExpansionAllowed" ItemsSource="{Binding Collection}" SelectedItem="{Binding SelectedItem, Mode=TwoWay}" ItemCountThreshold="{Binding CollectionItemsCount}">
(...)