For the scroll wheel, look at the right side of the screen (beyond the timeline) Do you see the verticle scroll bar? Does it indicate that there are more tracks that are unseen?
For the Horizontal scrool, do you have a video that extends beyond what you can see on the screen.
I just tried it on my mouse and tit scrolls (both directions) . I wonder if this is a Windows/Mouse issue rather than a PowerDirector issue?
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BoilerPlate: To posters who ask for help -- it is nice to thank the volunteers who try to answer your questions !
Anything I post unless stated with a reference is my personal opinion.