The callbacks from PlayerControl aren't used anywhere right now and there's only two unrelated internal functions in the GUI list menu with the same name. So the parameter checker emits a warning here.
Solve it by renaming the internal functions.
Previously, the em <-> pixels conversion was a hardcoded value. Now the GUI scales with the font size that can be selected in the options.
Sadly, all scales were off since the hardcoded value was too low.