All versions of Open Office including 1.9.109: 
When one types whitespaces at the end of a line of text, right up to the
margin-edge at the right hand side of the page, they do not show up even when
the non-printing characters are toggled ON. Furthermore, when one backspaces
from the next line down, all these completely invisible whitespaces must be
backspaced. This is an annoying inconvenience when editing a document with a lot
of text close to the right-hand edge of the page. The whitespaces seem to 'hide'
past the right-hand margin of the page and there is no way to know how many
white-spaces there may be past the margin of the page.

To reproduce the error: open a new document in Writer, turn on non-printing
characters, type a line of text until close to the right-hand margin, now type
spaces. Once at margin-edge all spaces disappear and extra spaces 'hide' beyond
the edge of the page.

Suggested fix: once at right-hand edge of page, whitespaces should be carried to
the next line down.