Why drag-into-CapCut never worked, not even once
A silent by-design ignore is indistinguishable from a broken feature. That is why it hid for so long.
Drag from Brolly into CapCut had never worked. Not flaky, never. So I debugged it evidence-first: the log file that should exist for every hand-off had never been created at all. No hand-off ever fired.
Root cause was a silent by-design ignore. Drops released over browser-owned windows were being swallowed on purpose, with no chip, no toast, and no log line. Reasonable-sounding decision, catastrophic in practice.
The lesson I am keeping: a silent ignore is indistinguishable from a broken feature. If the system decides not to act, it should say so somewhere, even if only in a log. Silence is how bugs buy themselves months of free rent.