Starting a Drag

A drag is started in one of two ways. First, the user may start a drag by pressing down Btransfer, the middle mouse button. As soon as the button is pressed down, the drag begins. Second, the user may start a drag by pressing and holding down Bselect, the left mouse button, and moving the cursor across the screen. The drag begins when the user moves the mouse a certain distance. This distance is called the drag threshold and it is measured in pixels. The default drag threshold is 10 pixels for Bselect. For Btransfer, the drag threshold is 0; because there is no drag threshold, the drag begins as soon as the pointer is moved. Motif scrolled text lists and text widgets are automatically registered as drag sources for text drags using Btransfer and Bselect.