XNEdit has two general types of selections, primary (highlighted text), and secondary (underlined text). Selections can cover either a simple range of text between two points in the file, or they can cover a rectangular area of the file. Rectangular selections are only useful with non-proportional (fixed spacing) fonts.
To select text for copying, deleting, or replacing, press the left mouse button with the pointer at one end of the text you want to select, and drag it to the other end. The text will become highlighted. To select a whole word, double click (click twice quickly in succession). Double clicking and then dragging the mouse will select a number of words. Similarly, you can select a whole line or a number of lines by triple clicking or triple clicking and dragging. Quadruple clicking selects the whole file. After releasing the mouse button, you can still adjust a selection by holding down the shift key and dragging on either end of the selection. To delete the selected text, press delete or backspace. To replace it, begin typing.
To select a rectangle or column of text, hold the Ctrl key while dragging the mouse. Rectangular selections can be used in any context that normal selections can be used, including cutting and pasting, filling, shifting, dragging, and searching. Operations on rectangular selections automatically fill in tabs and spaces to maintain alignment of text within and to the right of the selection. Note that the interpretation of rectangular selections by Fill Paragraph is slightly different from that of other commands, the section titled "Shifting and Filling" has details.
The middle mouse button can be used to make an additional selection (called the secondary selection). As soon as the button is released, the contents of this selection will be copied to the insert position of the window where the mouse was last clicked (the destination window). This position is marked by a caret shaped cursor when the mouse is outside of the destination window. If there is a (primary) selection, adjacent to the cursor in the window, the new text will replace the selected text. Holding the shift key while making the secondary selection will move the text, deleting it at the site of the secondary selection, rather than copying it.
Selected text can also be dragged to a new location in the file using the middle mouse button. Holding the shift key while dragging the text will copy the selected text, leaving the original text in place. Holding the control key will drag the text in overlay mode.
Normally, dragging moves text by removing it from the selected position at the start of the drag, and inserting it at a new position relative to the mouse. Dragging a block of text over existing characters, displaces the characters to the end of the selection. In overlay mode, characters which are occluded by blocks of text being dragged are simply removed. When dragging non-rectangular selections, overlay mode also converts the selection to rectangular form, allowing it to be dragged outside of the bounds of the existing text.
The section "Using the Mouse" summarizes the mouse commands for making primary and secondary selections. Primary selections can also be made via keyboard commands, see "Keyboard Shortcuts".