This question already has an answer here:
I wrote a custom
.sty file to put all my don't-want-to-carry-around definitions, which provides a new package for me. Now, if I want to use it with TeXstudio (that's what I use for typesetting), TeXstudio doesn't seem to find it (wiggly-underlines it as in "what's that package"). Whenever I want to use a command defined there, TeXstudio can't find it (won't autocomplete (as done with other packages) and highlights it as in "whoa that's a wrong command"), however compiles nicely without errors, as if everything was well-defined.
Why doesn't it recognize the package (and thus won't autocomplete or recognize the commands)?