If you currently select the opening keyword "function" in your PL/SQL code, all other occurence of "function" is highlighted. To me it would make more sense to additionally highlight the respective "end" keyword of the specific function instead of all "function" keywords in the package - like you get the "end if" of a block highlighted, after selecting its opening "if".
The same applies to preocedures.
The same applies to preocedures.