Multiple lines
==============

   Some expressions is too large for a single line, or one might want
to make some manipulations of the expression and then you need the
multiline function.  Simply press the Return key and the current line
is split in to two at position of the cursor. Joining the lines again
is done with Backspace or Del. You have to be on the outmost level of
line or the Return key will just work as the arrow down key - this
means you can't split a line in the middle of a fraction for instance.