Clicking an already-visible row was running ScrollIntoView+CenterRowInView via
the SelectionChanged → model PropertyChanged round-trip, yanking the viewport.
Add a clickInProgress flag separate from syncingSelection: clickInProgress is
set in OnTreeGridSelectionChanged and cleared at Background priority alongside
syncingSelection, so the model's two PropertyChanged notifications (Clear+Add
on SelectedItems) both bail out — but hyperlink / Back/Forward / search-hit
navigation, which never enters OnTreeGridSelectionChanged, still scrolls the
target into view.
Assisted-by: Claude:claude-opus-4-7:Claude Code
Siegfried Pammer
8e3a922b98