The output from Prolog (both stdout and stderr) is
redirected to this window. As output is being redirected
to this window, the window is scrolled so that the
insertion point is always visible.
Input to Prolog is also received from this window. When Prolog is expecting to receive a term (which also includes a query), the term will not be transmitted to Prolog until its full-stop is followed by a newline. This allows you to edit previously typed lines in a multi-line term before transmitting those lines to Prolog. When Prolog is expecting to receive input that is not a term, a newline will immediately transmit the line just typed.
The text that appears before the current prompt is not editable. You cannot type characters into this window while output is also being redirected into it.