[backport 11.0] Fix translation of DE component properties dialog close button

Something goes wrong with the usage of the German translation of the label of the Close button of the CM's component properties dialog. It should show the German ess-zett letter (unicode 0xdf), but it seems to be displaying a A-tilde (unicode 0xc3) instead. 0xc3 looks like some UTF-8 encoding isn't decoded before printing the character, because the UTF-8 encoding of 0xdf is 0xc3-0x9f.