Add borders to cells

What it does

Select a range and open the Borders button (the grid icon) in the toolbar to apply borders like Google Sheets. The popover offers a grid of ten modes — all borders, inner, inner-horizontal, inner-vertical, outer (box), the four single sides, and clear — plus a border color and a line style (thin / medium / thick / dashed / dotted / double). Pick a color and style, then click a mode to stroke the matching edges across the selection.

Applying a mode is additive across positions but a clean replace on each targeted edge (verified against Sheets): adding a top border then a left border leaves both drawn, and applying outer over all borders keeps the interior lines — but re-applying a mode over an edge re-paints just that edge in the current pen (change the style to thick and re-apply and the edge becomes uniformly thick, never a doubled line). Clear removes every border. The keyboard chord Ctrl+Shift+7 applies all borders (and toggles them off when the cell is already a full box).

Borders are presentation, separate from the cell's value: bordering =A1+B1 draws around the number without touching the formula. They undo and redo like any other edit.

Verified behavior

Matches Google Sheets: In Google Sheets the Borders toolbar button opens a popover with a grid of ten border modes — all, inner, inner-horizontal, inner-vertical, outer (box), the four single sides (left/top/right/bottom), and clear — plus a border-color picker and a line-style picker (thin/medium/thick/dashed/dotted/double, default thin solid black). Applying a mode sets the targeted edges of the selection to the current color+style and leaves other existing edges untouched (additive per edge); Clear removes all borders. Ctrl+Shift+7 applies all borders and toggles them off when the cell is already fully bordered. Borders are a presentation attribute independent of the cell's value or formula, and they undo/redo like any edit.

Ctrl+Shift+7 adds all borders (thin solid black) to the selected cell

Given

• A1 = x

When I click A1, then press Control+Shift+7

Then

• A1 is borders={"top":{"style":"solid","weight":"thin","color":"#000000"},"right":{"style":"solid","weight":"thin","color":"#000000"},"bottom":{"style":"solid","weight":"thin","color":"#000000"},"left":{"style":"solid","weight":"thin","color":"#000000"}}

Ctrl+Shift+7 a second time removes the borders

Given

• A1 = x

When I click A1, then press Control+Shift+7, then press Control+Shift+7

Then

• A1 is borders=false

borders are presentation only — the value is untouched

Given

• A1 = =2+3

When I click A1, then press Control+Shift+7

Then

• A1 shows 5
• A1 has formula =2+3