Changing display format for Foo* makes members inaccessible

Open simple.pro, build with a Qt built with MinGW, set a breakpoint in line 1158:

QStack<Foo> flist;

When breakpoint is hit, go to "Locals and Watchers", expand plist (sic!). Its members [0] and [2] can be expanded and their members can be analyzed. Select one of the pointer to Foo and "Change format for Type Foo*" to "Latin1-String".
Now the members are displayed as some strings and can't be expanded anymore. Change format back to "Bald pointer": The members still can't be expanded! To make the data accessible again, one has to restart Creator.