I never added support for modifying annotations in the companion app. This would involve a huge number of complex changes, as I would have to add all of the same annotation functionality in a different programming language using a different UI framework, and ensure that the annotations look the same on the PC as they do on the tablet (PC wouldn't have access to the same fonts as the tablet without additional work, for example). When I port MobileSheetsPro to Windows 8, that version will have support for annotations, so I may be able to transfer some of the changes over to the companion app. If I'm not able to do so, then I may add the ability to connect MobileSheetsPro on Windows 8 to an Android tablet in much the same way as the companion app...
On a side note, I do plan on supporting the ability to export annotations into PDFs/images themselves, making them a part of the file instead of just something that MobileSheets knows about. Once I add support for this, you could use any program on your PC to modify the annotations in the PDF.
Mike
EDIT:
Did I misunderstand you, and what you were saying is that you were unable to modify the annotations on the tablet after connecting to the companion app on your PC?
On a side note, I do plan on supporting the ability to export annotations into PDFs/images themselves, making them a part of the file instead of just something that MobileSheets knows about. Once I add support for this, you could use any program on your PC to modify the annotations in the PDF.
Mike
EDIT:
Did I misunderstand you, and what you were saying is that you were unable to modify the annotations on the tablet after connecting to the companion app on your PC?