VideoCapture opens wrong camera

[nickstr15]

Windows 10, Emgu.CV version 4.8.0.5324

The problem

I have two video input devices connected (my internal laptop camera and a analog video grabber (via USB)).
The key is, that sometimes the analog video grabber does not receives a signal or a is not even connected to the corresponding camera).

If I run

capture = VideoCapture(0); // capture laptop camera

the integrated camera is activated and I can read frames using capture.QueryFrame().

If I run

capture = VideoCapture(1); // capture from analog video grabber

and I have an input on the other side of the grabber everything works.

BUT if I run

capture = VideoCapture(1); // capture from analog video grabber

and the video grabber does not receives an input signal, the integrated camera gets activated and the frames of the integrated camera are received.

What i expect

Most importantly the capture instance should not switch to the other camera. Than, the QueryFrame()-method should not return a frame or an empty frame.