I'm currently making a frontend for my favorite expression-oriented arbitrary-precision calculator using PyQt4. The problem with it is that there doesn't seem to be any way to make part of a TextEdit widget read-only (specifically, the text that has already been sent and the results thereof) but the rest of it fully editable. Do I need to simply check for the cursor position and change the read-only status based on that, or is there some other widget or method that I am overlooking?