Another common use for drag and drop is to change relationships between objects. This is appropriate when the relationships can be represented visually. Drag and drop as a means of visually manipulating relationships is a powerful tool.
Cogmap is a wiki for organizational charts. Drag and Drop Object is used to rearrange members of the organization (Figure 2-23).
Figure 2-23. Cogmap allows organizational charts to be rearranged on the fly with drag and drop
When object relationships can be clearly represented visually, drag and drop is a natural choice to make these type of changes. Cogmap uses the target insertion approach. This allows the dragging to be nondistracting, since the chart does not have to be disturbed during targeting.
Bubbl.us, an online mind-mapping tool, simply highlights the node that will be the new parent (Figure 2-24).
Figure 2-24. Bubbl.us provides a visual indication of which node the dropped node will attach itself to
In both cases, immediate preview is avoided since it is difficult to render the relationships in real time without becoming unnecessarily distracting.
Looking outside the world of the Web, the ...