• In the "Grid" section, on the "Edit" tab, click "Mullions" to create a second field within the insertion:
  • Enter the position from the axis of the mullion or from the outer edge of the left frame and click "OK".
  • Click "Next" on the left side and define profiles, glazing and hardware.
  • Click "Main element" to save the changes on the insertion and to return to the to the main element that contains the floating window: