Data Tracker Grid with Keyboard & Mouse Navigation

In the first column, type your category names. Use Tab and Shift+Tab to indent or outdent. When a row has sub‐categories, click the triangle to collapse/expand. Only leaf rows let you edit numbers (columns 2–10); non‐leaf rows are computed. The top row (below the header) shows grand totals when it has children.

Keyboard Navigation:
- Navigation mode (default): use arrow keys (and Tab/Shift+Tab) to move between cells.
- Press Enter to switch to editing mode.
- In editing mode, press Enter to move to the next column or Cmd/⌘-Enter (or Ctrl-Enter) to move to the first column of the next row.
- Press Esc to return to navigation mode.
Mouse: Clicking on a cell updates it as the current cell. In navigation mode a click will not auto‐enter editing mode. In editing mode clicking a new cell maintains editing mode.