In Windows, every text editor I encountered allowed me to drag and drop any file type into it and it opened. Apparently, Mac app developers have a different philosophy because I can't find a simple free text editor for OS X that will do this. TextWrangler came highly recommended but it can't accomplish this simple feat. Can anyone suggest one?
Edit apparently on at least some editors, there is a distinction between drag/drop in the document list area vs. the typing area. In addition to the accepted answer, this is one thing to be aware of. I still don't know why it doesn't work in TextEdit, but this is true for TextWrangler and Smultron.