As it seems that some Dispatcher-Stations like Juliusz or DG Huta Katowice are not fully equiped with track-clearance indicators, it would be a very appreciable detail to enable the auxiliary light on the buildings to check for the end-of-train sign Pc5 at night.
My suggestion is to make use of the "3"-key, which currently does not seem to be functional in dispatcher-mode, to toggle the first-person camera at a position outside of the building´s windows, like if the player would stick his head out. Then, the player could the be enabled to move his first-person-camera around with the mouse as usual, while the focus of the light is centered in the middle of the camera.
In effect both the first-person view and the beam of light would be linked together, creating the impression that the player is controlling the light with his mouse while checking the Pc5-Signs at the end of the train. The screenshots below are to illustrate this idea.
Of course, since the reason for this suggestion is to enable a more realistic game-play, the light would have to be bright enough in-game to make the observation of Pc5 - signs at night/ in darkness graphically possible. Depending on how these lights work in reality, the devs would also have to introduce a new usable switch on the inside of the signal box I guess.