Generally, PDFreactor is not designed to create hardcopies of web pages as shown in a web browser or exact representations of the web browser view. PDF is by nature a paged medium with limited width and height, whereas the browser has one long, continuous view, with variable width. Because of this, the layout or design will usually be different in the PDF.
Also, PDFreactor doesn't use one of the common browser engines, but uses the in-house developed RealObjects MARTHA layout & rendering engine, which focuses on paged output and implements the W3C CSS Paged Media standard which is not or only partially supported in common web browsers. On the other hand browsers may include features that are not supported by MARTHA. This can also result in differences between browser view and PDF output.
Due to these general differences between paged and continuous media it may be necessary to use a separate style sheet for paged media output in order to get a proper layout. This print style sheet can either be added to the existing CSS section via @media rule or you set a User Style Sheet directly to your PDFreactor configuration. A documentation for both options can be found in our manual.