Is the code really used? I see that it is enclosed with #if 0/#endif in SetupGUILogging() in main.cpp
No, it is not.
The logging system is used and is working, but the
InfoPane is only used if you remove the
#if 0.
To elaborate, the logging system works in presence and in absence of GUI. Log data can be discarded, written to a file, shown on stdout, or whatever. This is not defined by the system itself, but by the individual loggers that are plugged in.
By default, all loggers are
NullLoggers. At application startup, those are replaced with more sophisticated ones (can optionally be controlled via commandline options too).
One such logger flavour is one that works as
NullLogger until it is asked to provide a control, at which time it starts logging to a
wxTextCtrl.
Now, the code inside the
#if 0 creates a notebook control, and asks all existing loggers for their respective controls, which it then adds to the notebook.
InfoPane is a plain normal notebook, with the one addition that it shows a popup menu to show/hide tabs. It can be any notebook class, and it doesn't need to be a notebook at all.