tracer4m traces calls to methods and functions.
Object-oriented design is about distributing responsibilities among interacting objects.
The objects should be small and focused. This results in a complex flow of calls.
Furthermore, in a GUI the user manipulates controls, which in turns trigger events and
chains of calls to methods and functions. There is a need to trace the calls.
The goal of tracer4m is to support unit testing, debugging, and analysis of existing code.
Example based on "Example - Using Events to Update Graphs" from the Matlab on-line help

feobject = fcneval( @(x,y) x.*exp(-x.^2-y.^2), [-2 2 ] );
fcnview.createViews( feobject );
log = TraceHistory.Instance;
log.setup( { 'fcneval', 'fcnview', 'createViews' } )
feobject.FofXY = @(x,y) x.*exp(-x.^.5-y.^.5);
disp( log )
%
log.clearHistory
feobject.Lm = [-8 3];
disp( log )

Part of the result is depicted in the image above.

Documentation: tracer4m_demo.html, which is generated by PUBLISH, discusses and demonstrate the use and behaviour of tracer4m.

I would appreciate comments especially regarding requirements on tracing tools for Matlab