A width change re-wraps every row at once, and with size restoration off
the accumulated height delta above the viewport threw the visible content
hundreds of pixels up and down while dragging the window edge. Size
restoration must stay off in steady state — a tool result expanding in
place has to grow downward — so a ResizeObserver on the scroll node
enables maintainVisibleContentPosition size compensation only while the
width is actively changing and releases it 300ms after it settles.
Measured on a continuous 1400-800-1400 drag over a long session pinned to
the live edge: the largest per-step displacement of a visible paragraph
drops from ~680px (median of three runs) to ~200px, and the viewport
never detaches from the end.
Bohdan Triapitsyn
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