Inside Qt assistant says: Note that if a widget is set as modified, all its ancestors will also be set as modified. Or, if you call setWindowModified (false) on a widget, this will not propagate to its parent because other children of the parent took have had been modified. See if I have any understand error: Note: if a widget is set to be modified, then all its ancestors will also be set to be modified. However, on this part if you call setWindowModified (false), so it will not affect its parent object, because it's father and other child objects have been changed... According to it is the child object call setWindowModified (true), then the parent object windowModified properties will change?? Or how do you understand???

CodePudding user response:

Every QWidget a windowModified attribute, if the window of document without saving changes, the windowModified is set to true, otherwise set to false,