src/vs/editor/common/cursor/oneCursor.ts/Cursor/_updateTrackedRange
class Cursor:	private _updateTrackedRange(context: CursorContext): void {
		if (!this._trackSelection) {
			// don't track the selection
			return;
		}
		this._selTrackedRange = context.model._setTrackedRange(this._selTrackedRange, this.modelState.selection, TrackedRangeStickiness.AlwaysGrowsWhenTypingAtEdges);
	}