MATLAB: Black bar in subsystem

MATLABsimulinkstateflowsubsystem

Dear matlab forum,
In one of the models I'm using the subsystens have all got a black bar on the in/output (see attached immage). Does anyone know what this means, what propery causes this, and how to turn it off? For consistency, I would like them to look like all other subsystems (i.e. no bars). The subsystem itself contains a stateflow model.
My hypothesis is that it is a subsystem property as I can remove the input bars by turning Block Parameters –> "Propegate exectuion context across subsystem boundary" on/off, but this only removes the input bars and turns the output ones white.
With kind regards,
Karel

Best Answer

From Mathworks support:
" The black rectangles on the input and output ports inside an enabled subsystem are shown when the option Display -> Signals and Ports -> Execution Context Indicator is turned on. So basically, these rectangles are execution context bars that shows that the particular subsystem runs in a different execution context than the root system. Here in this case, an enabled subsystem is executed only when it is enabled where as the root system is executed every time step i.e., this enabled subsystem is executed in a different execution context.
The details of this option is available at (search for ExecutionContextIcon)
https://www.mathworks.com/help/releases/R2019a/simulink/slref/model-parameters.html?searchHighlight=ExecutionContextIcon&s_tid=doc_srchtitle "
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