A really useful way for organizing the different parts of the model is using 'Layers'.

Open the Layers window by selecting the Utilities->Layer and groups option or clicking in the upper icons toolbar. The following window should raise up:

As it can be read in the upper part of the window, if user double click on that part, the Layers window is opened as an external window. User can choose to work with the Layers and groups window integrated or not.

All the actions related with layers and groups can be accessed by clicking the right mouse button onto the Layers and groups window. Most of them can be also used by the corresponding icon in the upper part of the Layers window.
By moving the mouse over the icons of the upper part of the window and staying 2 seconds onto an icon, a help message is shown in order to give the user information about the action associated with the icon.

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