An overwrite clipboard loses content
Aliases: clipboard overwrite · clipboard history · single-slot buffer
What it is
The default clipboard has one slot: the next copy replaces the previous object wholesale, and the displaced content has no document-level undo. When someone prepares two passages for two pastes, the second copy makes the first vanish from the global buffer. The loss is not a delete key. It is the structure of a single-slot overwrite.
Why it happens
Single-slot semantics equate “the clipboard” with “the most recent copy.” Working memory can watch several passages in transit; the machine can watch one. Any copy in between—including an automatic system write, a format painter, or a mistap—commits an overwrite. If the overwritten object is gone from the source (cut not copy, source closed, source a ephemeral message), there is no second copy. Clipboard history turns the slot into a stack or list: new writes push on top, old objects can still be picked for paste. History is not “one more copy command.” It admits that overwrite drops things, so the slot becomes reviewable. Without history, the only loss-prevention strategy is paste-then-copy-the-next, chopping the task into strict copy–paste–copy–paste, which fights the human strategy of “collect, then distribute.”
Studying it
Give a task that must move n passages, with only a single slot or with a history buffer. Log losses, time spent re-finding the source, and whether people switch to strict alternation. Independent variables include n, whether the source still exists, and whether history items are visible. Dependent measures include overwrite loss and voluntary history opens. An n=1 task cannot show this.
Where it stops holding
“Copy to a dedicated target” (share sheet, drag, send to a field) does not walk the global slot; overwrite is not this claim. Version history of a collaborative document can recover the source, not the overwritten object that lived on the clipboard. History itself has a length cap and a privacy cost; it is not an infinite stack.
Applying it
- Offer clipboard history or a pinned slot for multi-item transfers; keep single-slot paste of the latest item as the default.
- If history is unavailable, treat cut more cautiously than copy before an overwrite, or leave the source in a wastebasket-like buffer.
- Accept with “collect three passages, paste to three places.” If success on a single slot requires switching to alternating copy-paste, overwrite is breaking the task strategy.