very slow edits when rows/columns are Grouped with Outliner.

[vic]

Edits like just writing a cell (ex, typing a number over a cell) or deleting a cell ("Del" key) take very long (5 secs on my computer) when many rows/columsn are grouped and collapsed ("Outliner" tool).
Ungrouping same rows, or removing the grouping entirely, makes the same edits very fast (well under 1 sec on my computer).

See attached files; go to sheet "large", column CN and type in cells, delete cells... while groupings are collapsed or not