When the Simulation Tool encounters a nondeterministic situation, a Non-determinism dialog box opens.
The Non-determinism dialog box displays the name of the chart that the non-determinism occurred in along with a number of possible solutions. You are able to toggle all possible continuations by using the up and down arrow keys. There is also a field showing the name of a Statechart in which the non-determinism occurred. This helps the you to know which chart should be examined in order to select a desired continuation. Once an acceptable solution is chosen, the OK button confirms this choice and you can proceed with simulation.
Note: If the non-determinism is an undesirable behavior, you can choose to modify the chart(s) and rebuild simulation.