Grouped rows and columns now get Excel's outline band beside the headers:
a bracket per group, a -/+ button on the summary line and level buttons
in the corner. The buttons run data.hideDetail / data.showDetail and the
new data.showLevels, so they undo. Hide Detail marks the summary line
collapsed, Show Detail keeps inner groups that were collapsed on their
own, and Group / Ungroup take by: rows|cols. Show Detail and Hide Detail
are on the Data tab and in the Data menu, the group shortcuts are listed
as Alt+Shift+Right / Left, and shortcut lookup reads navigation keys by
their logical key so the numpad arrows work.
Fixes#373
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Fill Series by month used the previous cell's day as an overflowing DATE()
day, so Jan 31 + 1 month became Mar 3 and February was skipped. The same
overflow affected year steps from Feb 29 and the autofill month pattern.
Each item is now computed from the start date plus n months and the day is
clamped to the target month's length (Jan 31, Feb 28, Mar 31, Apr 30), so
the clamp does not compound. Leap years are handled.
Fixes#132
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Excel documents the first argument of MIN as optional and returns 0
when there are no numbers. MIN was registered with a minimum of one
argument, so =MIN() returned #VALUE!. The aggregate already returns 0
for an empty list, so only the registered arity needed to change.
Fixes#138
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
