Watermarks are *supposed to be* behind the text. What do you want to happen
instead?
To fiddle with various effects, do this:
- Open the header area in the page or section containing the watermark.
- Click on the watermark, so it shows the little "handles" around the sides
and corners.
- If the Picture toolbar isn't visible, click View > Toolbars > Picture.
- On the toolbar, click the Text Wrapping button (its icon is a dog on a
hatched background). In the dropdown menu, select any of the choices except
"In line with text". See what the various choices do.