The calculation of the lateral stability is fully based on the Eurocode 1992-1-1 in article 5.9.
There are two situations with different limits for lateral stability. The transient and permanent situation can be checked. If the limits are overreached it does not mean that the beam loses its stability, but you have to use a higher type of analysis. The higher form of analysis is not implemented in IDEA StatiCa Beam.
Watch the recording of one of our webinars, where the calculation of lateral stability was performed.