At this time this model is still not ready for having its components redefined. Everything is highlighted in the same color because the model still consists of one body only. They are all highlighted in green because this one body is being considered as ground and green is the color which is representative of the ground body. Mechanism Design will not allow ground components to be assembled via connections to other ground components. Therefore ALL of the components have to be removed from ground first before any of them can be redefined.
Last selection becomes grayed out.
You may also observe that before selecting Unsel Last all the components in the model tree are highlighted and graphically they are all red on the screen. As Unsel Last is selected the components in the model tree will no longer be highlighted and they will turn white on the screen. This model is finally ready to broken down into separate bodies with Mechanism Design Connections. As mentioned earlier the components of this model will be redefined one by one starting from the bottom of the model tree. Select 'Yes' to reuse its placement constraints for defining connections.