Is there any way to set the default applications that DTP uses to open documents when “Open With…” or “Open Externally” is chosen? If not, are there any plans to include this in future versions? Thanks.
You could use the OS X method of setting the default application for all files of the same type.
Example: In the Finder, click on a JPEG image file. Press Command-I to show the Info panel. You can set the application to open the file, e.g., GraphicConverter or PhotoShop Elements. Then you can set this as the default for opening all JPEG files. Once that is done, Open Externally will open the image under the application you have designated.
Similarly, you could set all PDF files to open externally under Preview, or under Acrobat Professional 7.x.
There have been requests for an added option in DT/DT Pro, to set the Open With application for an individual file. The developers are aware of this request.