On linux .h files won't color the braces until we choose "c++ starting kit" syntax

this is an odd issue, and only happens on linux (on windows it works fine):

when using the oasis theme, the braces get a red color. but when we open .h files under linux the braces are white (everything else is fine) and won't be color red until i choose "c++ starting kit" as the syntax.

thanks in advance.