Midi- and instrument track pop-up program selector window resets when selecting a program, making it impossible to select another program in the pop-up program selector window while open.
This was working in Cubase 12, where the selected program is kept at the selected position and where it is possible to select another program with mouse or arrow keys, without the program selector pop-up window to be closed.
The way it is working in Cubase 12 is very handy when searching and scrolling through large program lists to find programs or patches.
Just saying: I reported this issue some weeks ago: Program selector jumps back to the top of the list - Cubase - Steinberg Forums
A possibly related issue that when I try to use the cursor up and down keys to navigate in the list, it is not possible. The one and only Greg Ondo could reproduce the issue in a Cubase Hangout.