Hi there, @PanThyMush
It sounds like you'd prefer that the mobile app cursor offer a press-and-hold feature to get really granular on the scrub bar on the YouTube channel, is that correct?
Do you have a physical remote that you can try with, or is this only happening when using the mobile app?
Keep in mind the majority of channels on Roku, including YouTube, are programmed and hosted by the provider -- In this case, the functionality would be on YouTube/Google to provide as we don't program how their channel interacts. But, try the physical remote, and let us know what you find. If you don't have a physical remote, shoot me a PM and we'll see what we can do.
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