Why can't I see instantiated objects with the Simulink debugger?

I have some embedded matlab code inside a Simulink simulation and I'm instantiating some objects. When I step through with the debugger and set a breakpoint in the embedded matlab, I can see all the other local variables (as expected) but I cannot see the object or do anything with it that I normally could when stepping through with the Matlab debugger (outside of Simulink). The code does still run, I just can't see it in the debugger.

Any idea why? Is there a way around this?

Thanks

[TAB]

Can you share part of your code ?

[dvd7e]

Sure. As a simplified/dummy model, my Simulink is just a Matlab function, with the following code:

function y = fcn()

% Create the car object at simulation startup
persistent bmw
if isempty(bmw)
    bmw = car('bmw'); % Instantiate the car object
end

% Every time step move the car's position
bmw.move(1);

% Output the current car position
y = bmw.pos;

and this is the class definition for a "car":

classdef car < handle

     properties
        name = '';
        m = 1000;
        pos = 0;
     end

     methods
         function obj = car(nameIn)
          obj.name = nameIn;
         end

         function obj = move(obj,stepVal)
             obj.pos = obj.pos + stepVal;
         end

         function obj = resetPos(obj)
             obj.pos = 0;
         end
     end
  end

When I run this in Simulink it behaves as expected. Every iteration it moves the car position by 1 and outputs that position. The issue I'm seeing is that when I use the debugger to step through and put a breakpoint in the embedded matlab, I can't see the car object or any of its methods or properties. I usually can do this with the Matlab debugger, but apparently not in Simulink. On the other hand, I can see "normal" variables in the debugger, like the output "y".

Without being able to interact with the objects from the debugger/command line, it makes it much harder to debug or investigate what's going on.