Pass pre_command to CommandDialog as const reference to avoid unnecessary copying.
addMatching and insertFromParent functions from FocusableList now avoid copying m_parent->clientList() and use a const reference instead.
doSubmenu function in menutest.cc avoids copying labelstr by using a const reference.
Reduce the scope of the variable err in stringTokensBetween.
Initialize m_index in MenuItem's constructors.
Make Layer::getLayerNum() const.
ButtonTheme::name can be const.
TextBox::textStartPos can be const.