I tend to find the bag frame namings very hard to work with.
If you open all your bags (standard hotkey "b" or OpenAllBags()), they are named ContainerFrameX, where X starts with 1 (your standard bagpack) and increases by 1 for each additional bag. If you open a single bag, it is always named ContainerFrame1. So no matter how many bags you open, the first one always is ContainerFrame1, even if it has another number when opening all bags at once.
If I walk through every bag looking for a certain item, how can I save a reference to find this item again when the user only opens one bag afterwards? I don't want to search for it again.