I've been bulk-buying carnival items with the view of fragmentising the common ones and selling/hoarding the rare ones, but found that, unlike the Vault, Inventory doesn't have a "tick these items and vault them in bulk" functionality.

I can click an item and vault it, but I cannot Ctrl+r it for multiples of the item - each one has a unique ID and "Inventory -> Item -> 'Send to vault' -> you're in inventory again, return to step one" is very tedious and I've had enough tedium with buying...

OK, think I, there is the option to unstack the stack: Stacking: Yes | No Then I'll Ctrl+click all the rare+, then Ctrl+Tab through them and, because "to Vault" button is roughly in the same place, that should work relatively quickly! Right?

Wrong.

The first item of a kind in the list works. Every duplicate item after it sends me to "https://subeta.net/item.php?itemid=" and, as can be expected, suggests that Oh No! No itemid specified [Back to Last Page]

So, despite visual appearance of unstacking, the items do not, in fact, become separate identities to be used in separate ways, which I believe to be a bug.

(having checkboxes, like in Vault, would be handy, too! In Inventory I can't bulk-select items, in Quickstock I can't sort them by rarity, that's such an awkward situation :/ )

yes, this has been a known problem since forever. It does need to be fixed, but don't count on it being done anytime soon.

My workaround is to use the vault. I have categories and I keep my main vault section mostly empty and just toss all new stuff into the vault then sort, check and deal with the items in there. Its not ideal, takes an extra step, but its much faster than trying to deal with individual items in inventory.