What is the best way to show the user that a state is active?

Hi!

I need to show the user that a state is active with some kind of widget.

As an example:
The user imports a picture of a face into the program. He or she draws a mustash on the face. At the same moment the user has started the editing of the picture, the widget that showing if the picture is edited is checked. When this widget is once checked it can't be uncheked. The point with this is to letting any other user loading this file knowing if the picture he or she sees is a original or a edited version of the picture.


I thought that a checkbox should do the job, but the problem is that the user should not be able to change it's state and I can't find any way to make this possible. I found out that a QLineEdit can do something smiliar:

Code:

---

/* This makes the lineEdit clickable and selectable but not editable, but I only want to 
*  to use true/false so QLineEdit would not be my first choice.
*/
QLineEdit stateLine;
stateLine.setReadOnly ( true );

---

How can I do this with a checkbox? Or do you know about some better widget that I can use?

thanks
pir

disable the checkbox once it is checked.