I am working on windows universal app,In this app when i use tab and alter + tab then ,the application automatically terminate and show this error .I just captured a picture so you can see.
This type of error is due to some logical error, resulting in the object having a null value. The main cause of this is when a Combobox does not get an index, causing the app to crash. Sometimes the XAML code can cause this but does not detect or inform you about the error.