The current token is displayed in red. Run Allows you to run the simulation step by step. To advance to the next token click with the mouse anywhere on the screen. Current state and transition taken are marked in red. You will also see the current token marked in red in the input string.
Simulation aborts if an error condition occurs.
Watch the status line on the bottom for the explanations. When the end of the string is reached the status line will inform you if the string was accepted by the machine or not. If the last state is marked accepting it will be highlighted in blue, signifying acceptance. Stop Aborts the current simulation in progress and returns to editing mode.