question

In case anyone finds this topic in the future let me complement this thread with the FloWorks answer: because FloWorks does not use time slicing but events, you need to make sure that the engine is aware of ports being opened or closed so the flow rates through your network can be recalculated. In pre-17.2 FloWorks separate commands CloseFlowOp and CloseFlowOutput were provided that you had to use instead of FlexSim's closeop and closeoutput. Since version 17.2 FloWorks supports 'dot syntax' which allows you to write:

// Note: type of the variable is FlowObject instead of Object
FlowObject flowObject = model.find("...");

// "Red bar" for all output, just like in regular FlexSim
flowObject.output.close();

// Close a single port, equivalent of 'old' closeop/CloseFlowOp
flowObject.output.ports[1].close();

or directly through

// note the use of .as(..) to ensure that the treenode is treated as flow object
model.find("...").as(FlowObject).output.close();
model.find("...").as(FlowObject).output.ports[1].close();