In Windows 8 Store apps, if a combobox is included inside a popup like a normal fly out, and the selection changed event causes the pop up to close, and the App running on ATOM processor machine, then the App will crash most of
the times. This issue just happens on ATOM processors.
The Reason: Since there’s a ComboBox inside a Popup, when the ComboBox’s Selection Changed event fires, the outer popup gets closed. If garbage collection (GC) happens
to come in at exactly that point, it exposes a ref count problem (The GC causes the VisualState to go away, but the ComboBox is still on the call stack and wants to use
Temporary fix: Try to change your app logic to avoid closing the pop up at the time of selection changed event
This issue was reported to Microsoft and a request for fix has been submitted and they did a hot fix which solved this issue.