Open Radar

 
Summary:
I would like to use OmniGraffle to document complex design relationships in my project. To that end, I would like to be able to view (not necessarily edit) OmniGraffle files that I've added to my XCode project. This way, I can use the "Open Quickly..." command and other keyboard shortcuts to toggle between my source and my design docs - without leaving XCode. 

When I add PDF file, JPG files and even DOCX (Microsoft word) files to my project, clicking on the file name shows me what I would see when I select the file in the Finder and hit 'Space' to invoke QuickLook.

However, in the case of .graffle files, clicking on the file in XCode shows me the XML.  When I click on the same .graffle file in the Finder, and then hit 'Space' I see the graphical representation of the OmniGraffle file.

I have attached a sample XCode project that has an OmniGraffle file added to it.

Steps to Reproduce:
1) Create an XCode project, or open an existing XCode project. 
2) Add an OmniGraffle file to the project
3) Select the file in the File Navigator in XCode

Expected Results:
XCode displays the same visual representation of the file that the Finder displays for QuickLook.

Actual Results:
XCode displays the XML contained in the .graffle file

Version:
XCode Version 6.1.1 (6A2008a)
OS X Version 10.10.2 (14C109)

Notes:
Exporting the .graffle file to PDF and adding the PDF to the project is a workaround, but the risk is that the PDF and the .graffle file could get out of sync. Another workaround for that is using something like Hazel to keep the PDF and .graffle file in Sync.