When using a multicharacter separator in a string, the expand function will insert a blank row between the separated strings.
E.g.:
gives the following content for 'a' (3 rows):
Why does it do that?
E.g.:
a:='abcxxdef'; expand('xx',a);
gives the following content for 'a' (3 rows):
---- abc def ----
Why does it do that?