The PFE editor has extensive macro possibilities and it can serve as a Dynamic Data Exchange (DDE) server. This DDE feature is used when pressing the "Compile" button in 4TeX. By pressing this button a DDE command is issued to save the file in the PFE editor, and hence you do not have to save the file before you compile it. Also the DDE is used for block compilation. You can simply mark a block in your text and by right-clicking the "Compile" button, only the marked block is compiled and displayed. This block compilation makes it easy to check complex mathematics and tables without compiling the whole document. When an error occurs during compilation, you can jump to the line of the error by typing the "e" and then pressing "Enter".
Of course you can change the complete functionality of the editor and the LaTeX macro tool by changing the 4TEX.INI file.
There are also two shareware editors that are ready to be used by 4TeX: MED and WinEdt. These editors offer syntax highlighting and much more. Note, however, if you use any of these editors you should register and pay for it. The editors PFE, MED, and WinEdt all support DDE. See the documentation on DDE for details on this item.