Column and row resize (drag, auto-fit, and multi-select)

What it does

Drag to resize. Hover the border between two column-letter (or row-number) headers — the cursor turns into a resize handle — and drag to set that column's width (or row's height). A dashed guide line tracks the pointer while you drag; the size commits when you release.

Double-click to auto-fit. Double-clicking a column-header border sizes the column to fit its widest non-empty cell's content (using the same canvas text-measurement the grid renders with), plus a small margin. Double-clicking a row-header border does the same for height — though rows already auto-fit their content live as you type, so this mainly matters after a manual drag: it reverts the row to that automatic content-fit height.

Multi-select resize. Select several columns (or rows), or the whole sheet via the top-left corner box, then drag or double-click any ONE of the selected borders — every selected column/row resizes together. A drag applies the same width/height to all of them; an auto-fit fits each one independently to its own content, so a multi-column auto-fit can land on different widths per column.

Persists. A resized column/row is an explicit size override, distinct from the default/auto-fit geometry. It round-trips through Save/Load and Export JSON (colWidths/rowHeights, keyed by column/row index, schema v5) and Export XLSX (column width in Excel's "characters" unit; row height in points).

Verified behavior

Matches Google Sheets: In Google Sheets, dragging the border between two column-letter headers (or row-number headers) resizes the column/row to the left (or row above) of the dragged border, with a live vertical/horizontal guide line while dragging. Double-clicking that same border auto-fits the column/row to the widest (or tallest) NON-EMPTY cell's rendered content in it, plus a small padding margin; double-clicking an empty column/row's border is a no-op (it stays/reverts to the default width/height). Selecting multiple columns (via a shift/drag multi-column header selection) or row headers, or selecting the whole sheet (the top-left corner box), then dragging or double-clicking ANY ONE of the selected borders resizes/auto-fits every selected column/row together — a drag applies the SAME width/height to all of them, while an auto-fit sizes EACH one independently to its own widest content (so a multi-column auto-fit can produce different final widths per column). A resized column/row is an explicit override that persists with the file (reload / re-share shows the same widths) and is exported with the sheet. This is long-standing, widely-documented Sheets/Excel behavior, not something ambiguous enough to need live verification against the reference workbook; a follow-up can add the features/column-row-resize.oracle.md study-sheets brief if a review finds a discrepancy.

Dragging a column border sets an explicit width that persists across save and reload

Given

When I drag column B's header border by 60px, then save, reload the page, and load the workbook back

Then

• column B is exactly 160px wide

Double-clicking a column border auto-fits it to its widest content

Given

• B1 = A considerably long piece of text that overflows the default column width

When I double-click column B's header border (auto-fit)

Then

• column B is at least 300px wide

Auto-fit on an empty column is a no-op (stays at the default width)

Given

When I double-click column D's header border (auto-fit)

Then

• column D is exactly 100px wide

Dragging a row border sets an explicit height, independent of content auto-fit

Given

When I drag row 3's header border by 40px

Then

• row 3 is exactly 61px tall

Double-clicking a row border reverts a prior drag back to the

Given

When I drag row 2's header border by 40px, then double-click row 2's header border (auto-fit)

Then

• row 2 is exactly 21px tall

Selecting multiple columns, then dragging one selected border, resizes them all together

Given

When I click the B column header, then press Shift+ArrowRight, then drag column C's header border by 50px

Then

• column B is exactly 150px wide
• column C is exactly 150px wide