CDB: return value not shown by Qt Creator debugger

According to http://doc.qt.io/qtcreator/creator-debug-mode.html#local-variables-and-function-parameters :

The Locals view consists of the Locals pane and the Return Value pane (hidden when empty).

Whenever a program stops under the control of the debugger, it retrieves information about the topmost stack frame and displays it in the Locals view. The Locals pane shows information about parameters of the function in that frame as well as the local variables. If the last operation in the debugger was returning from a function after pressing Shift+F11, the Return Value pane displays the value returned by the function.

However, this does not work in my environment. Minimal example to reproduce:

debugger_return_pane.pro:

TEMPLATE = app
SOURCES += main.cpp
TARGET = DebuggerReturnPane

and here is main.cpp:

int foo()
{
    return 0;
}

int main()
{
    int x = foo();
    return x;
}

Steps to reproduce:

• set a breakpoint on the first statement of main()
• lauch the debugger
• F11 (steps into foo())
• Shift+F11 (steps out of foo())
• problem: no return value visible

The problem was acknowledged by aha_1980: https://forum.qt.io/topic/99119/return-value-not-shown-by-qt-creator-debugger/7