Created attachment 48455 [details]
test files

Here is how to reproduce the bug (all files mentioned can be found in
the attached zip):

1. On Ubuntu Desktop 11.04 with LibreOffice 3.3.2 or MS Windows XP
with LibreOffice 3.4.0 set the colors of the desktop theme so that the
window background in LibreOffice Draw is white.

2. In Draw create a drawing without a background color (which is the
default setting) -- see Draw_test.odg.

3. Export the drawing as PDF (File -> Export as PDF) -- see
Draw_test1.pdf. The PDF file has a white background.

4. Change the desktop theme to use a non-white background, e.g. as shown in
Ubuntu_Customized_Theme.png and WinXP_Modified_Theme.png. 
(A user may do this as the default white is too bright for him/her.)

5. Export the drawing to Draw_test2.pdf (on Ubuntu) and Draw_test3.pdf
(on Windows). The background color in the PDF file is the same as the
drawing window background color. I'd say this is a bug as the
background color in PDF should be white by default if the document
doesn't have an explicit color.

6. If the page background color is explicitly set to white in Draw
(Format -> Page -> Background -> Fill -> Color: white) you get
Draw_test4.pdf - also not good.

-- rpr.