see https://wiki.mageia.org/en/Feature:InstallerLeftSideRedesign
in short, it means the left side of the installer could be partly clickable/partly dynamic changed depending on various options chosen or via which method/media you're installing. ie: it looks differently if you're using live or DVD or network install and some consistency in the steps. if you're in a certain step, that step should be active and not the next/previous step.
