Mouse chording

Mouse chording is the capability of performing actions when multiple mouse buttons are held down, much like a chorded keyboard. Like mouse gestures, chorded actions may lack feedback and affordance and would therefore offer no way for users to discover possible chords without reference. A similar feature such as a context menu would require less training.

In the X Window System, and on some laptops with integrated 2-button mice, a three button mouse can be emulated using a chorded click from both the right and left buttons which is translated into a middle click. This middle-click emulation does not enable chords which involve the middle click. The Apple Mighty Mouse does not support mouse chording due to the design of the button sensors.

One common application of mouse chording, called rocker navigation, is found in Opera and in mouse gesture extensions of Mozilla Firefox. Rocker navigation typically involves the following two mouse chords:

• Hold the left button and click the right button to move forward in the browser's history.
• Hold the right button and click the left button to move backward in the browser's history.

The operating systems Plan 9 and Oberon and the acme development environment make heavy use of mouse chording. OS/2 Presentation Manager can also use chording to copy and paste text using two buttons however Common User Access key combinations are more frequently used.

Applications that support mouse chording

This is an incomplete list, which may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

• Microstation - CAD software, uses chording to snap to elements.
• CATIA - CAD/CAM/CAE software, uses middle and left mouse button chording to zoom, pan and rotate screen representation
• Acme and Wily
• Opera
• Maxthon
• Blender 3D
• Plan 9 from Bell Labs
• Oberon operating system
• Sketchup
• Valve Hammer Editor
• Celestia - Pressing both mouse buttons allows the user to adjust distance from an object.
• Minesweeper (Windows) - Pressing both mouse buttons clears around a square after the correct number of flags have been placed in the surrounding squares.
• UDE
• World of Warcraft
• Grand Theft Auto: San Andreas - The weapon aiming system in the PC version of San Andreas implements mouse chording, as it requires the user to hold the right mouse button to aim while clicking or holding the left button to fire a weapon or use an item, such as a camera.
• Eve Online - Pressing both the left and right mouse buttons allows for an alternative method of camera control.
• Tom Clancy's Rainbow Six: Vegas 2 - On the PC version of the game, by default the right mouse button must be held to take cover and the left mouse button to fire a weapon.

External links

• acme manual page, describes the various chords in acme
• rio manual page, describes chording inside the Plan 9 window system
• Copying and Pasting using the Mouse, describes chording in OS/2.