It's useful to be able to view the contents of plain text files in the document pane.  I *think* the following is accurate - would appreciate corrections - 

 

If you use File > Import From > Text File(s), the path to the plain text file will be stored in the FilePath and FileName fields; the name of the file will be stored in the Item field.  A copy of the file contents will be stored in the ItemHTML field (for embedded storage), or the file referenced in the ItemHTMLFile field.  You can edit the original external plain text file in an external editor by double-clicking on the Item.   You can edit IQ's copy of the content in the document pane.  The resulting content of the copy will be HTML, not plain text.  In this case you've just got to be aware that you're working with two separate versions of the same content, and changing one will not change the other.

 

If you drag and drop the text file to IQ, and select the "No Hyperlink" and "Doc Pane" options, the path to the plain text file will be stored in the ItemHTMLFile field.  The text of the external plain text file will appear in the document pane.  I thought that if I edited the plain text file in the document pane, that it would be converted to an HTML document, i.e. HTML tags etc would be inserted.  But I have discovered that this does not happen!  Text can be added or deleted, the file can be saved, the changes are there, and it remains plain text.  If I try to insert some formatting, like making some text bold, and try to save the changes by pressing Ctrl+S, or clicking the Save button, that change is simply lost.  But the good news is that we can display external plain text files in the document pane, and edit it them there, without concern that they might be accidentally converted to HTML files.