Omnigraffle 7.5 assumed “All objects” when exporting a document to PDF, which is what I want. Omnigraffle 7.8 assumes “Entire document”, which is not what I want (does anyone? Why?), so I have to remember to reset it every time if I don’t want TexShop to say that the image is too wide.
Some OmniGraffle users export the entire document if they are exporting a multiple-page PDF, or if they have created fixed size content for printing. Each document remembers the last export settings used for that document (if it has been exported before). You should only need to set the scope to “All objects” one time. The next time you export that document, your settings should be remembered. If there are any cases where your export settings are failing to save, please let us know.