The InvisibleButton drag-trap inside BeginChild only catches clicks
inside that specific child. Chat had widgets OUTSIDE the inner
##chattail child (the Copy-mode Checkbox + a Separator at top, the
footer Separator + InputTextSubmit at bottom) — empty space around
those widgets fell through directly to the parent window's
window-drag init.
Fix: wrap the entire chat panel body in a single outer ##chatbody
BeginChild before drawing any content. The renderer's drag-trap
fires inside this outer child too, absorbing every empty-space
click in the chat panel body. The inner ##chattail child is now
nested inside it, which doesn't change its scroll-tail semantics
but does mean it gets its own drag-trap as a bonus.
Test fixed: Render_BeginChild_ReservesNegativeFooterFromFrameHeight
was using Single(BeginChild) — there are now two BeginChild calls
(##chatbody outer + ##chattail inner). Switched to Single(... &&
Args[0] == "##chattail") so the test still pins the footer reserve
on the inner call where it lives.
dotnet build green; 1,309 / 1,309 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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