The solution to this is pretty obvious once you think about it.
Press down and hold on the Left button
Move the Trackball to the right , left, down or up and ignore the selected text
once you reach the point you want to read, edit etc.
just release the left click
then click once again anywhere on the sheet / page to switch focus
Why would I want to do this?
It saves you having to move the cursor over to the right or bottom scroll bar whenever you want to scroll through the page