Reprint: http://forum.ubuntu.org.cn/viewtopic.php?f=42&t=239517 I use the Apple Wireless keyboard, began to encounter the same problem, and later found the answer on the forum, as done on the OK.
Change Function Key behavior
This section of the document describe the behavior of the "FN" key to better match what user expect. (see #201711, #162083)
Here a description of each behavior:
0 = disabled:disable the ' FN ' key. Pressing ' fn ' + ' F8 ' would behave like you only press ' F8 '
1 = fkeyslast:function keys is used as last key. Pressing ' F8 ' key would act as a special key. Pressing ' fn ' + ' F8 ' would behave like a F8.
2 = fkeysfirst:function keys is used as first key. Pressing ' F8 ' key would behave like a F8. Pressing ' fn ' + ' F8 ' would act as special key (Play/pause).
Ubuntu 9.04 and newer
Temporarily
This section describe the behavior of ' FN ' with immediate effect (restarting'll reset the configuration). Execute the following commands to the Fnmode parameters. See sections above for a description of available value.
$ sudo bash
# echo 2 >/sys/module/hid_apple/parameters/fnmode
# exit
Mac keyboard opens FN function button under Ubuntu
