Copy pasting Visio documents

I easily with no fuss managed to copy paste a visio document into a word
document and save as a doc file. The document opened as originally drawn and
saved.
More recently the document when opened has a grey background and I cannot
remove it. I have tried copy pasting the original visio flow chart into a
word doc and it still changes the background to grey once in a word format.

Any ideas would be useful.

Thanks