CppEditor: Auto corrections of '.' to '->', triggering auto-completion or the proposal widget do no more work

Steps to reproduce:

• create a simple main.cpp using Qt
• put some pointer objects into the code
• enter the variable name, type a '.' and wait for getting automatically corrected to '->'

• replace the '.' by '->' manually and hit 'Ctrl+Space' - proposal widget does not come up

• add an include to something unique and type the first parts of the object's name and hit 'Ctrl+Space' - it won't be automatically completed

Current result:

• nothing happens