[Lazarus] Lazarus Package Library (lpk) - Linking question

[Krzysztof]

Hi,

For example BGRAControls package. If I drop TBGRAButton on form,
Lazarus automatically add BGRAControls package as required in project
inspector. Then, If I build project, it seems that compiler adds all
controls from this package to exe even if I don't use them, because if
I delete BGRAControls package from required section and add path to
BGRAButton unit manually, then exe is much smaller. How does it work?
Exists any compilator optimization switch for strip unused units from
project packages?

Regards, Dibo