I know diagonal lines can be drawn on schematics. After checking the manual, still can not find it.
While adding a wire (is that what you mean by a line in the schematic?) press the F3 key and change the Draw Mode from the default of "route" to something that allows diagonal or any angle wires.
I think this is what you are looking for, but if not, supply more details and you might get further help.
In reply to skillUser:
This is exactly what I am looking for. Thanks a lot.
In reply to Frank Chen:
I preffer another way. When I drawing a wire I click the right mouse button until schematic editor will be entered into "Any angle" mode.
In reply to fomin:
It is the Right Mouse Button (RMB) to "Toggle Drawing Mode" using the IC5141 release, but this is now the Middle Mouse Button (MMB) in the IC61x releases.