I had to connect with gmail account to watch the video. I hope they won’t spam me .
The cell is not selected it is in grey. When I select a cell in a listbox, the line is in blue. And then another cell in another listbox the line in the previous listbox become grey.
I suppose it’s because you personalised the colors.
To answer your topic question: No.
The first listbox loses its focus when the second is selected. That’s the blue border and works as expected.
It does not lose its selection automatically. If you want to attain this, you should use the LostFocus (or whatever the current event name might be) event to also deselect the selected row(s).
Sometimes such irregular behaviour can also be triggered when a ListBox selection/focus event is overridden but returns the wrong Boolean, so you find yourself working against the OS.
BTW, you find the exact same behaviour in the Navigator where an object can be selected but not have the focus so you have to click the row again to make keyboard commands work.