C#: Inconsistent accessibility: property type
<p>What's wrong with </p>

<pre><code>public partial class MainWindow : Window
{
    public ObservableCollection&lt;TabViewModel&gt; Tabs { get; set; }
    public ICollectionView TabsViewSource { get; set; }
    public int CurrentIndex { get { return TabsViewSource.CurrentPosition; } }
</code></pre>

<p>I get </p>

<blockquote>
  <p>Inconsistent accessibility: property type 'System.Collections.ObjectModel.ObservableCollection' is less accessible than property 'TabsRendering.MainWindow.Tabs'</p>
</blockquote>

<p>when i change the code to </p>

<pre><code>public partial class MainWindow : Window
{
    ObservableCollection&lt;TabViewModel&gt; Tabs { get; set; }
    public ICollectionView TabsViewSource { get; set; }
    public int CurrentIndex { get { return TabsViewSource.CurrentPosition; } }
</code></pre>

<p>It works. Whats wrong with the <code>public</code> on the <code>ObservableCollection</code></p>
