shortcut for naming object in windows

dear mitmaxers,

i desperately seek for the (working) keyboard shortcut for naming an
object. i know that it's + as the menu says, but on the German
windows keyboard from my laptop it does not work. i tried several
combinations but they're all not leading to the naming window.

can someone help me out and relieve me (or better my right hand)
from constantly switching between mouse and keyboard?

thanks in advance

micha