Ability to 'lock' Qt classes

BACKGROUND
While working on Qt based project, I accidentally refactored (using CTRL+SHIFT+R) QString to QStringList. This refactor propagated through every Qt header file.

FEATURE DESCRIPTION
The feature requested here would be to have a lock option in the Creator preferences to prevent modifications to all Qt header files, and have this enabled by default on installation. 'Following Symbol Under Cursor' feature should still allow viewing of headers, but editing should be prevented unless explicitly allowed by the user.

JUSTIFICATION
It is probably the most common use case that users of Qt Creator are looking to use Qt libraries rather than modify. Anyone who wishes to modify Qt libraries would need to open the source files anyway which aren't included with the Qt Creator download (to my knowledge) and so would not really be affected by this lock.