This is one of the issues with PTP (Picture Transfer Protocol) which is a subset of MTP (Media Transfer Protocol). Since HoneyComb your Android device sets up as a MTP device when connected to a PC and by design, MTP devices (like PTP devices) are not treated as a traditional removable drive. The actual file system is implemented by the device, not by the computer's operating system. Basically files created on the MTP device are not seen through a USB connection until the device is forced to reread the file structure refreshing the MTP information, as you have seen when you rebooted your Nexus 7.
As a workaround, save the document to your Google Drive and access it through Google Drive on your PC.