- The workbook's active sheet is an atomic set in place (Workbook::active_sheet /
set_active_sheet), so a window swap or sheet switch never clones the
Arc<Workbook> or marks it dirty. Selections already live in DocState and the
window views. Save records the sheet of the most recently active window.
- A dialog taken out of its window while it runs goes back to that window when
a command run from it switched windows (dialogs::show, ui.dialog.confirm).
- view.arrangeAll {arrange?: tiled|horizontal|vertical|cascade, activeWorkbook?}
returns the visible windows, active first; the desktop moves and sizes the
native windows over the main window's monitor. New Window and Arrange All
buttons on the View ribbon; Arrange Windows dialog.
- Docs: ui-parity, hardware-parity, gaps #20, target-app-parity, ROADMAP.
Session keeps a window list (stable ids, per-window selection, active sheet
and per-sheet selections swapped into the workbook without dirtying it)
in place of the index-based hidden list and the copying New Window.
Titles read Name:1 / Name:2 for a workbook with several windows.
File > Close closes one window of several; window.close, window.list and
window ids for window.activate, view.switchWindows, view.hideWindow and
view.unhideWindow. Control channel and MCP tools take window/doc ids;
scroll positions and cell drafts belong to their window.