'Ctrl' + '-' shortcut to make font smaller doesn't work

Currently, on the latest version of this app available on Apple App Store you can make the font size bigger with 'ctrl +' but the shortcut 'ctrl -' isn't recognized so you cannot make the font smaller.

Also It would be great to have the possibility of resize the font just by the canonical keyboard shortcut 'cmd +' to make the font bigger, or 'cmd -' to make font smaller. Where Cmd stands for Command key (typical of Apple's keyboards)