TrEd can be controlled either by keyboard or mouse. There are several pre-defined keyboard hotkeys to move the active-node (cursor) along the tree, to cut or paste subtrees and nodes (i.e modify the structure) and to open the dialog where attributes for the active node can be edited. Trees can also be easily modified by clicking and drag-and-drop. Both of these approaches are described below:
Clicking left or right mouse button on a node activates it.
Double clicking left mouse button on a node invokes Node->Edit Attribues command.
Double clicking left mouse button on the text of a node's attribute opens a prompt for editing the value of this attribute.
Dragging active node with left mouse button moves that node with its subtree to the new location. If user releases the button near another node, the active node becomes son of that node.
Dragging active node with right mouse button has the same effect but if the tree is too large to fit the window, the window “scrolls forward” as user gets near its edges.
Dragging mouse with the middle mouse button pressed has the same “scrolling effect” described above, but no node is moved.