FixedDocumentSinglePagePresenter uses simple rendering mechanism using UIElements, which currently has some limitations:
- Layers are not supported, thus annotations and forms are not rendered (even read-only)
- UIElements could be affected (clipped) when UseLayoutRounding property set at parent level, when DPI is different that 96 DPI. 

Workaround: If content is clipped, ensure that UseLayoutRounding is set to false as presenter level:
<telerikUI:FixedDocumentSinglePagePresenter UseLayoutRounding="False" />