When simming 'my' territory Copenhagen Ringsted I naturally end up having a lot of trains running and therefore also many "Stacked Routes" lined up in the "CTC Stacked Routes" window. The window has a fixed size and can not be expanded. You have to scroll by clicking with the mouse. Very cumbersome if you are busy.
In such a busy territory I tend to accidently make the same stacked route more than once for the same train movement, because the previous I made was on the part of the stack that extends beyond the window size.
Please make the window expandable! :-)