Tested with FLTK1.1.7 under Win2k, german keyboard:

Some words before:
The output texts show heavy flickering, while 1.1.6 snapshots (r4586) don't.
See a layout of a german keyboard e.g. at this link:
http://en.wikipedia.org/wiki/Keyboard_layout

Now my observations:
event_text() shows the proper symbol all the time.
Exceptions (probably not related to the different keyboard layouts):
Shift right presses the proper key on the visual keyboard, but shows FL_Shift_L as event_key.
Keypad enter shows FL_KP+'^M', but triggers the normal enter on the visual keybord.

event_key() seems to show US mappings, in particular (not all keys tested):
(Pressed / shown)
'+' / '='
'#' / '/'
'^' / '\'
The swapped 'y' and 'z' map properly.