Repurposing "menu" button on Windows keyboards used in OS X

Question

Windows keyboards map pretty intuitively to OS X, leaving only the "context menu" button a little purposeless. I would like the menu key to behave as another Command key.

How does one define what the "context menu" key on Windows keyboards does in OS X?

On this keyboard, the "context menu" key is directly under the "." (period/greater than) key; on the bottom row between "alt" and "ctrl" on the right side, two keys to the left of the "left arrow" key. What does it do in OS X, and what is it called?

Answer 1

It has neither purpose nor name in OS X.

Maybe Karabiner could do it, if you can figure out what key code it sends - try Key Codes to see if it generates anything usable.

Answer 2

Starting with macOS 10.12 Sierra this can be accomplished from the command line using the hidutil utility as described in Technical Note TN2450.

Using the table of key usage IDs at the bottom of the technical note you can find the IDs of the Application (i.e. context menu) key and the right GUI (i.e. command) key as 0x65 and 0xE7 respectively. Therefore the mapping can be done from the command line as follows:

hidutil property --set '{"UserKeyMapping":[
    {
        "HIDKeyboardModifierMappingSrc": 0x700000065,
        "HIDKeyboardModifierMappingDst": 0x7000000E7
    }
]}'

The mapping won't survive reboots, but can be made persistent using a launchd agent by placing a property list such as the following in the appropriate launch agent directory (for instance ~/Library/LaunchAgents for your user):

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.local.KeyRemapping</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/bin/hidutil</string>
        <string>property</string>
        <string>--set</string>
        <string>{"UserKeyMapping":[
            {
                "HIDKeyboardModifierMappingSrc": 0x700000065,
                "HIDKeyboardModifierMappingDst": 0x7000000E7
            }
        ]}</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

Answer 3

Doing @Steph's answer but with Karabiner:

1. Install Karabiner from here
2. In "Simple Modifications" tab, select your keyboard (mine was this "Microsoft.." one)
3. Press on "Add item" to make those 4 modifications in the screenshot below

This will map your keys to be as follows:

Answer 4

To expand on @Tetsujin's answer: you can indeed achieve this with Karabiner. Here are some detailed instructions.

In short: go to the Misc & Unistall tab, open private xml, change it to:

<?xml version="1.0"?>
<root>
  <item>
    <name>Menu key to option right</name>
    <identifier>private.menu_key_to_OPTION_R</identifier>
    <autogen>__KeyToKey__ KeyCode::PC_APPLICATION, KeyCode::OPTION_R</autogen>
  </item>
</root>

Go back to the Change Key tab, click Reload XML, and tick the new mapping you just made at the top of the list.

Karabiner has its own keyboard EventViewer in the Misc tab, so you don't need KeyCode.

Answer 5

I found that Seil works to change the "context menu" key to the 'Option' function (I presume it would work to change to 'Command' as well, although I have not tried it) in El Capitan.

In 'System Preferences... | Keyboard' I changed the 'Option' to 'Command' and 'Command' to 'Option', so that the keys are in the same order as on my MacBook Pro, to facilitate "muscle memory".

Then in 'Seil Preferences | Setting | Keys on non-Apple keyboard' I checked 'Enable Application Key (Menu Key)' and set the keycode to '54' (according to 'Seil' this is 'Right Command', but probably because of the switch in 'Keyboard' it functions as 'Option'.

So that gives me this:

Answer 6

Karabiner doesn't seem to support OS Sierra yet but Karabiner Elements does. Installing it takes a bit of work but once you've done that you can map "application" to e.g. "right_command" to make it work like you described.

Answer 7

Repurposing "menu" button on a notebook's Windows keyboard in MacOS 10.12+

There is a new version of Karabiner ("Karabiner Elements 12.1" to be used with MacOS 10.12+) that imho justifies adding a separate answer to this topic, though I posted s.th. similar here before.
[ As I did upgrade to MacOS 10.13 (High Sierra) I had to use ApplePS2SmartTouchPad.kext to be able to re-map the "menu" button, which is now seen as scan_previous_track. ]

With Karabiner Elements you have to edit its ~/.config/karabiner/karabiner.json file, somewhat differently** to the above code …

First find out "menu" button's name on your keyboard via Karabiner EventViewer:
just press it once. [Mine is: scan_previous_track, yours' probably different … ]

Here is some code analogue to parts of what I posted above, opening & closing "Information":

{"description": "Finder: 'menu' key to æ-I / æ-W by pressing or holding",
    "manipulators": [
        { "conditions": [{ "bundle_identifiers": ["^com.apple.finder"],
                                         "type": "frontmost_application_if" }
                        ],
                "from": { "consumer_key_code": "scan_previous_track" },
          "parameters": { "basic.to_if_alone_timeout_milliseconds": 200,
                          "basic.to_if_held_down_threshold_milliseconds": 500
                        },
         "to_if_alone": [{ "key_code": "i",
                           "modifiers": ["right_command"]
                        }],
     "to_if_held_down": [{ "key_code": "w",
                           "modifiers": ["right_command"],
                           "repeat": false
                        }],
        "type": "basic"
        }
                    ]
}

  (If pressed briefly Cmd-I is triggered, after holding the button for half a second: Cmd-W)

– from, to… and type are mandatory expressions for re-mapping
– conditions, parameters define exclusively affected app(s) and time thresholds for events**
– "repeat": false keeps this code from unintentionally closing more than one window
– This code would be inserted between "rules": [ ]'s brackets (possibly with "," added)
    (I made shortcuts for my browser's history-back and -forward function with press & hold, too)
– Have a look into Karabiner Elements json Reference Manual …

(** KE no longer supports conditional selection by uielementrole, but a few other conditions.)

Answer 8

I use MacOSX 10.11.6 El Capitan (from a broken Mac mini) on an hp-2570p EliteBook, so the Windows menu-key isn't recognized as "PC_APPLICATION" but simply as "FN" = function key.
Unfortunately this key blocks secondary keys so I had to do some more elaborate twitching to get where I wanted:

Using Karabiner (with integrated EventViewer for information on keys/names/windownames) I reused the key to:
– mimic æ-i in Finder (repeat for closing)
– mimix æ-i in VLC ( – " – )
– do history-back in Safari
Further I made other non-menu-key changes:
– redefined some keys that aren't labeled correctly on my German keyboard
– made access to pageUp/Down "one-handed" on my keyboard (not shown)

I'll probably find some more simplifications in other applications over time ...
I used this "individual" code in "private.xml" (details: see post by antoine):

<!-- 1st item redefines <,>,^,° for my keyboard (effective for further items !!!)
<item>  
    <name>Switch_specialKeys_^_°</name>
    <identifier>private.Switch_specialKeys_^_°</identifier>
        <autogen>__KeyToKey__ KeyCode::BACKQUOTE, ModifierFlag::SHIFT_L, KeyCode::GERMAN_U_UMLAUT, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
        <autogen>__KeyToKey__ KeyCode::BACKQUOTE, KeyCode::6, ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L</autogen>
        <autogen>__KeyToKey__ KeyCode::DANISH_DOLLAR, KeyCode::BACKQUOTE</autogen>
        <autogen>__KeyToKey__ KeyCode::BACKQUOTE, KeyCode::DANISH_DOLLAR, ModifierFlag::SHIFT_L</autogen>
</item>

<!-- Next 2 items differentiate "Cmd-i/-w" via (not-)AXWindow for dual use -->
<item>
    <name>WinR-FNDR æ-I</name>
    <identifier>private.WinMenu_to_Cmd-I</identifier>
    <uielementrole_not>AXWindow</uielementrole_not>
    <only>FINDER</only>
        <autogen>
          __KeyToKey__ KeyCode::FN, KeyCode::I, ModifierFlag::COMMAND_L
        </autogen>
</item>
<item>
    <name>WinR-FNDR æ-W</name>
    <identifier>private.WinMenu_to_Cmd-W</identifier>
    <only>FINDER</only>
    <uielementrole_only>AXWindow</uielementrole_only>
        <autogen>
          __KeyToKey__ KeyCode::FN, KeyCode::W, ModifierFlag::COMMAND_L
        </autogen>
</item>

<!-- For VLC the <uielementrole_only> elements are "AXWindow" for the main
     window and "AXRadioButton" for its information window. -->

<!-- My shortcut for Safari's "history-back" consists of this definition:
     <autogen>
        __KeyToKey__ KeyCode::FN, KeyCode::CURSOR_LEFT, ModifierFlag::COMMAND_L
    </autogen>      -->

For PC applications running under CrossOver the application names aren't recognized by Karabiner, so I used <appdef> to (re)define their names and <windownamedef> to address a particular window; these definitions were then available in <only> and <windowname_only> tags.