Behavior of the mouse in general, and the naming of the buttons is covered in the chapter on the overall user interface (see Chapter 8, Introduction).
Within the hierarchical display, elements which have sub-hierarchies are indicated by when the hierarchy is hidden and when the hierarchy is open.
Button 1 click over the name of any diagram artifact will cause the diagram to be selected and displayed in the editing pane. Its details will also be displayed in the details pane.
Button 1 click over the name of any artifact other than a diagram in the main area of the explorer will cause it to be selected, and its details shown in the details pane. If the artifact is part of a diagram currently displayed in the editing pane, it will be highlighted there.
If the artifact is part of a diagram other than that currently displayed in the Editing Pane, there will be no change of diagram in the Editing Pane.
Where button 2 click has been used to bring up a context sensitive pop-up menu (see below), button 1 click is used to select the menu entry required. button 1 click outside the menu area will remove it.
This has the effect of a button 1 single click, and if the tree item was not a leaf, it will toggle the hierarchy open or close.
Button 1 motion means that you pick up one or more modelelements, and drag them to a new location. Dropping the modelelement somewhere causes ArgoUML to execute some function that depends on where you drop the modelelements.
Releasing the mouse button above a namespace, makes the modelelement owned by the namespace. In the Package-centric explorer perspective, this means a straigh-forward drag-and-drop function.
Use this drap and drop feature to easily move e.g. classes from one package into another.
Dropping a modelelement on the diagram is the equivalent of the "Add to Diagram" function. Hence, if the diagram did not yet show this modelelement, it is added.
Use this drap and drop feature e.g. to easily create a diagram from imported XMI files. This because XMI files contain all the modelelements, but not any diagram information.
When used in the the explorer, this will display a selection dependent pop-up menu. Menu entries are highlighted (but not selected) and sub-menus exposed by subsequent mouse motion (without any buttons). Menu entry selection is with button 1 or button 2.