Fade in problems in Cubase 4

I’m still using my old and good Cubase 4. Recently I ran into a new problem: when editing a a track, I cannot make a fade in like I always did anymore. I used to place the cursor in the up right little square of the track and drag it as far as I wanted my fade in to work. An oblique line would then be dried. Now, when I do this, a vertical thin line follows the square direction and no fade in is done. Can anyone tell me how to solv this problem, please?

Thank you!!!