Unmovable operations are operations assigned to a particular workstation and which can not be moved elsewhere by the automatic line balancing tool. Unmovable operations have their station number drawn in red as shown in the following figure.

The operation named "Oper 6" is unmovable and assigned to the station 2. The two other operations are assigned to the workstation 5, but can be reassigned to another station in case of automatic line balancing.     Unmovable operations are also painted with a red bar in the workstation view and in the operator view, as shown in the figure below.

Unmovable operations in the Operators Tab

• To change the movable/unmovable status of an operation, switch to the Workstation Tab, right-click on the desired operation in the line or detail part of the Tab, and then choose the movable/unmovable menu option. Note that setting the workstation (WS option in the popup menu) to movable/unmovable only changes the status of all the operations currently assigned to the workstation.
  

    While the unmovable status constraints the assignment of an operation to one particular workstation, it is also possible to constrain an operation to a set of workstations, with zoning constraints.