You can drop a text file (.xml, .sgm, .txt, etc) onto an empty Arbortext Editor window to open it. If you want to insert a file into an existing document, you can hold down CTRL as you drop. These files are not context checked until the mouse button is released, so if the file cannot be inserted, an error message will be displayed. You can also insert a file as an entity by holding down SHIFT and CTRL as you drop. An entity is defined (if the document was not previously identified as an entity), and an entity reference is inserted.