In Analytics Builder>Settings you can specify "Signals/Profiles Per Page".
On the Signals page the top part listing the models isn't expandable, so you can see at most 5 entries without scrolling.
That means, if "Signals/Profiles Per Page" is set to 10 and you have 6-10 signals, you have to scroll, if you have more, you need to scroll AND use paging.
The bottom part is expandable, but only to fulls screen.
The idea is to make it an adjustable pane, so the users can drag the dividing bar to the size they need. (Like the vertical divider on the left side for the Thingworx menu, which can me manually adjusted in width)
Or at least increase the standard size of 5 visible entries.