If you were in a laboratory with a real (physical) instrument, you would not expect to get meaningful measurements from an ohmmeter in a circuit with power applied. You might even damage the instrument.
Most physical ohmmeters supply a small current to the resistance being tested and measure the voltage across it. Then the resistance is calculated from Ohm's Law. I think the simulated ohmmeter works similarly, although I do not know how much current it applies.
Lynn
