Instead of a scrolling marquee, if you would want "bouncing text" then you can put a label inside a rectangle. Turn off the label's borders, turn on the rectangle's borders, and then set up your form timer to move the top & left of the label by some non-zero but small fixed amount. It might not be a good idea to try to move things too fast, though, because fast timers can be a real drain on resources.
Check for that moment when the invisible borders of the label "touch" the borders of the rectangle. When it happens, change the fixed "move" amount based on which borders collided. If it was top or bottom, swap the sign of the vertical move amount. If it was left or right, swap the sign of the horizontal move amount. If you do it that way, you can move as little as one twip at the time (twips of course being the size/placement unit of all controls on the form.)
In this approach, if the label is very big with respect to the rectangle, it becomes impractical because you will not move very far before you change direction again. It will not be smooth even with a small move increment in that case.