In the Lateral buckling parameters field of the Member Definition - Parameters (CAN/CSA-S16) dialog you can specify om2. This coefficient is used to account for increased moment resistance of a laterally unsupported doubly symmetric beam segment when subject to a moment gradient (as specified in Section 13.6 of the code). It can be defined manually, by typing a value from the range (1.0, 2.5) in the om2= field, or by selecting one of the icons from the Coefficient om2 dialog. To open this dialog, click the icon next to the om2= field.
You can select one from 3 icons: