The Library Navigator pane shown in the figure below enables you to use the contents of both the on-line Web library of Holobloc Inc, which is contained in the src.zip file and updated automatically (if necessary) by the FBDK at startup, and of your local file library (located in the src folder of your local FBDK directory, e.g., C:\\fbdk8\src\ in Windows™ operating systems).

Library Navigator	Editor

The location of a library element is indicated by the prefix of the element's name in the Library Navigator:

• A ">" prefix indicates that the element is located in the Web library; for example, the ASEL_UINT FB type in the above figure.
• A "+" prefix indicates that the element is located in the Web library and also has a copy (whose contents may be different from the Web library element) in the local file system; for example, the X2Y2 FB type in the above figure.
• An element name with no prefix exists only in the local file system; for example, the NewBasic FB type in the above figure.

The type of a library element is indicated by its icon in the Library Navigator as shown below.

Operations that can be performed in the Library Navigator include:

• Selection - i.e., clicking on an element, for instance, the X2Y2 FB type in the example below - will cause the selection of the corresponding tab (if it exists) in the Editor area to the right of the Library Navigator.
  • Selection of a tab in the Editor area will also select the corresponding element in the Library Navigator ("two-way synchronization") if an element with the tab name is currently in the library.
• Double-clicking an element in the Library Navigator will open it for editing in a tab of the Editor area.
  • If the element is already open in a tab, this will just select the existing tab.
• Deletion of an element in the local library can be done from its pop-up menu in the Library Navigator.
  • An element in the Web library cannot be deleted, but its local copy may. This will cause the element's prefix in the Library Navigator to change from "+" to ">"
  • The menu will not pop up unless the element is in the local library and is not open in a tab of the Editor area.
• Drag and Drop (DnD) can be used to add a graphical element to a diagram in the Editor area by dragging from its type element in the Library Navigator and dropping on the desired location in the diagram.
  • Dropping of a graphical element is only allowed when it is consistent with the IEC 61499 information model; for example, an instance of a Device type can be dropped into a System diagram, but not into a diagram of the contents of a Resource.
  • When feasible, dropping the element on the diagram will open a dialog in which you can specify a name and comment for the dropped element.
  • DnD can also be used to change the type of a graphical element by dropping on the instance name that appears above the block outline (the name acts as a "handle" for manipulating the block). This operation is only allowed when:
    • both the instance name and body of the element are the same (non-white) color, indicating that the element is editable; and
    • the new type is the same kind of Library Element as the old type, e.g., a Function Block type cannot be dropped on a Resource; and
    • the interface of the new type is a proper superset of the interface of the old type, i.e., it contains at least all of the interface declarations of the old type.