Strange would have thought the keyboard viewer layout is closer to the real thing.
There is one more key to map on the L shaped enter keys but why such a key that is used in so many short cuts moves its location strikes me as really strange.
I cannot get CMD+' to work anyway I try or switch layouts around.
What is really strange though is that
here on the german short cut manual
they actually say the exact same thing CMD´.
You know where the ´ is on a normal german layout?
Left of the backspace. That is not enough you need the Shift key too.
I was finally curious enough to hit the Restore Defaults buttons.
Alt+CMD is my work after all. Seriously they make millions of $ whatever in Europe and have a hundreds if not thousands of people working on stuff and cannot find the one man to spend maybe a a couple hours to properly localize short cuts.
It does kind of fit the picture with Apple German keyboard layout which is different than the normal one but not for the better. [] are next to impossible to find and not where they are on any normal keyboard. Kind of important keys for programming.
Still the OP's problem should be solved by assigning something better than ctrl F4 to that one action.