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Environment

  • OSX 10.7.4
  • Mid-2010 iMac
  • VirtualBox 4.1.18
  • Ubuntu Precise Pangolin (all updates applied)

Issue

I have created a fresh VirtualBox vm and installed Precise from the standard desktop ISO. As a part of the install I selected the 'English UK (Mac International)' key-map. All of the keys seem to be emitting the correct character, however, for some keys a character will not be registered until I have pressed the key twice.

For example, the first time I press the ` key no character appears at the terminal prompt. However, the second time works.

This also happens for some other keys and shift combinations - ie ~ (shift + `) is also affected.

Further info

  • This does not appear to be a VM issue. I installed Precise under VMware Fusion and the exact same problem seems to occur.
  • It isn't related to the speed that I'm typing. I can press the key, wait a couple seconds, then press it again and I get the same behaviour.
  • Switching to an alternative keyboard layout (English UK extended WinKeys) the problem persists for the backtick character (you must press the § key on the keyboard). Pressing the ` key emits a character () immediately. In other words the problem seems to be related to specific characters, rather than the hardware codes emitted by particular keys.

xev output

First keypress:

KeyPress event, serial 30, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3935772, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: True

KeyRelease event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3935884, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XFilterEvent returns: False

Second keypress:

KeyPress event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3939630, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: True

KeyPress event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3939630, (317,33), root:(320,141),
    state 0x0, keycode 0 (keysym 0x60, grave), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 1 bytes: (60) "`"
    XFilterEvent returns: False

KeyRelease event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3939777, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XFilterEvent returns: False

Third keypress:

KeyPress event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3956078, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: True

KeyRelease event, serial 33, synthetic NO, window 0x4a00001,
    root 0x138, subw 0x0, time 3956214, (317,33), root:(320,141),
    state 0x0, keycode 94 (keysym 0xfe50, dead_grave), same_screen YES,
    XLookupString gives 1 bytes: (60) "`"
    XFilterEvent returns: False

The additional "grave" key press only seems to be emitted every other physical key press.

share|improve this question
    
Have you tried just changing the keyboard layout to something else? –  Bruno Pereira Aug 12 '12 at 11:43
    
Bruno, I have tried changing the keyboard layout and updated my question to indicate that it seems to be related to particular characters rather than physical keys. –  johnstok Aug 12 '12 at 13:04

2 Answers 2

It seems that the keyboard map is incorrect for these keys. The simplest solution is to make the following corrections via xmodmap:

$ xmodmap -e 'keycode 94 = grave asciitilde'
$ xmodmap -e 'keycode 48 = apostrophe quotedbl'

To have these modifications applied at login you can create a file called .Xmodmap in your home directory with the following contents:

keycode 94 = grave asciitilde
keycode 48 = apostrophe quotedbl
share|improve this answer

Just an addendum to Johnstok's answer. Add

keycode 94 = grave asciitilde
keycode 48 = apostrophe quotedbl

to file .Xmodmap in the home direcotory and run

xmodmap .Xmodmap

For me this did the trick, but it reverted to the old way every time I rebooted. I had to put xmodmap .Xmodmap into my .bashrc file to get it to stick.

share|improve this answer

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