Comment 1 for bug 746795

Commenting out the callback definition for the recent manager "changed" signal seems to make this problem go away, so you probably have a problem in this callback (or the GetRecentFiles method that it calls). I don't know C#, so I can't tell where the problem could be.

void OnRecentChanged (object sender, EventArgs e)
{
    // We update Files here because this is called on the main thread.
    // We call ToArray so that Files is immutable and safe to enumerate.
    items = GetRecentFiles ().OfType<Item> ().ToArray ();
}