When using key keymap "de(neo)" - layout German with variant "neo" - walking through windows using Alt-Tab does NOT work. Not even the pop-up showing the window or application symbols does appear.

When using the keymap "de" or "de(nodeadkeys)" - layout German with variant "no dead keys" - walking through windows using Alt-Tab works as expected.

Version: kdebase4-workspace-4.11.16-5.mga5

How to reproduce:

- Press Alt+tab to verify walking through windows works in your set-up.
- Change the keymap to "de" (standard german keymapping):
    $ setxkbmap -layout de
    $ setxkbmap -query
    rules:      evdev
    model:      pc105
    layout:     de
    options:    compose:rwin
- Press Alt+tab to verify walking through windows still works
- Change the keymap to "de(nodeadkeys)" (Germany keymapping commenly used by programmers):
    $ setxkbmap -layout de -variant nodeadkeys
    $ setxkbmap -query
    rules:      evdev
    model:      pc105
    layout:     de
    variant:    nodeadkeys
    options:    compose:rwin
- Press Alt+tab to verify walking through windows still works
    $ setxkbmap -layout de -variant neo
    $ setxkbmap -query
    rules:      evdev
    model:      pc105
    layout:     de
    variant:    neo
    options:    compose:rwin
- Press Alt+tab -- nothing happens

Notes

1. It does not matter whether you change the keymap via setxkbmap, via KDE system settings or via some X11 config file. All of these ways result in the same xkb settings as you can verify using setxkbmap -query.

2. When "de(neo)" is active, xev shows key-events for "Alt" and "Tab", while for the other keymappings only "Alt" is shown an the Tab seams to be intercepted by the window manager.

    KeyPress event, serial 40, synthetic NO, window 0x4400001,
        root 0xd4, subw 0x0, time 41792235, (1456,682), root:(1456,705),
        state 0x10, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
        XLookupString gives 0 bytes: 
        XmbLookupString gives 0 bytes: 
        XFilterEvent returns: False

    KeyPress event, serial 40, synthetic NO, window 0x4400001,
        root 0xd4, subw 0x0, time 41793075, (1456,682), root:(1456,705),
        state 0x18, keycode 23 (keysym 0xff09, Tab), same_screen YES,
        XLookupString gives 1 bytes: (09) " "
        XmbLookupString gives 1 bytes: (09) "       "
        XFilterEvent returns: False

3. Then temporary deactivating the shortcut for walking through windows, xev show exact the same output even for plain "de" layout.

4. "de(neo)" is the only X11 layout redefining the *upper* layers of the Tab-key:  
          key  <TAB> { [ Tab, ISO_Left_Tab, Multi_key, ISO_Level5_Lock, NoSymbol, NoSymbol, NoSymbol, ISO_Level5_Lock ] };
    while all other layouts use
        key  <TAB> {  [ Tab, ISO_Left_Tab ]   };
    The key definitions can be found in /usr/share/X11/xkb/symbols/de: grep '<TAB>' /usr/share/X11/xkb/symbols/*