Original sentence: Moreover the system was slow and documents saved from this software suite were not viewable in applications which did not support OpenDoc's Bento format — that is, practically all of them
Edited sentence: Additionally, the use of the leading edge OpenDoc meant that documents saved from this software suit were not viewable in applications which did not support the Bento format — that is, practically all of them.Moreover the system was terribly slow, although the reasons for this are not obvious