cell-selection

Register cellSelectionFeature with tableFeatures, provide a getRowId option, then bind cell.getSelectionStartHandler() to onMouseDown and cell.getSelectionExtendHandler() to onMouseEnter on each cell. Both handlers are required for drag selection to work.

Call table.selectCellRange(range) to replace the selection, or pass { mode: 'include' } or { mode: 'exclude' } to add or subtract a rectangle. Ranges are defined by anchor and focus corners identified by row and column ids.

Ranges are anchored to corner row and column ids, not fixed positions, so sorting or reordering recomputes what sits between the corners and can widen the selection. Call table.resetCellSelection(true) after such changes if stricter behavior is needed.

This happens when only the mousedown handler is bound. You must also bind cell.getSelectionExtendHandler() to onMouseEnter; without it a drag selects only the origin cell. Do not add a mouseup binding since the start handler manages its own.

Call table.getSelectedCellRangesData() to get raw values as a [range][row][column] structure, then serialize to TSV in your own code before calling navigator.clipboard.writeText. The table returns raw values only; delimiter and quoting rules are application decisions.

Yes, selection resets to initialState.cellSelection whenever data changes, because new data can invalidate the row ids a range references. Set autoResetCellSelection: false to opt out, though autoResetAll overrides this option.