Dictionary.net

A common method for manipulating files (and sometimes text)under a graphical user interface or WIMP environment. Theuser moves the pointer over an icon representing a file andpresses a mouse button. He holds the button down while movingthe pointer (dragging the file) to another place, usually adirectory viewer or an icon for some application program,and then releases the button (dropping the file). The meaningof this action can often be modified by holding certain keyson the keyboard at the same time.Some systems also use this technique for objects other thanfiles, e.g. portions of text in a word processor.The biggest problem with drag and drop is does it mean "copy"or "move"? The answer to this question is not intuitivelyevident, and there is no consensus for which is the rightanswer. The same vendor even makes it move in some cases andcopy in others. Not being sure whether an operation is copyor move will cause you to check very often, perhaps every timeif you need to be certain. Mistakes can be costly. Peoplemake mistakes all the time with drag and drop. Humancomputer interaction studies show a higher failure rate forsuch operations, but also a higher "forgiveness rate" (usersthink "silly me") than failures with commands (users think"stupid machine"). Overall, drag and drop took some 40 timeslonger to do than single-key commands.[Erik Naggum ]