Thank you for your post.
Can you describe a bit more what you mean by a smaller window? I have several text fields inside a tab, and I can enter information where I can zoom in and out with two fingers. What is in the smaller window? A portal? An image?
I found the answer to my issue.
But in response to your question - I have a table that is in a srollable window inside one of my tabs in a form layout. I was not able to scroll using the scroll bar. But what I have now learnt - in order to scroll you need keep your finger pressed against the scroll bar - and it turns into a large bar, thus allow yoiu to scroll !