The itemsControl data source list is already empty, but there is still one element displayed on the UI. The developer tools indeed indicate that it is empty, yet one element persists.

[rocinn]

[rocinn]

Is it possible that the modification of the data source in a sub-thread is causing this?

[rabbitism]

Yes, collection should be updated with dispatcher.

[kyuranger]

sub-thread

It is so strange that my collection always updates by sub-thread but never causes this.