src/vs/workbench/contrib/terminal/browser/terminalGroupService.ts/TerminalGroupService/setActiveGroupByIndex
class TerminalGroupService:	setActiveGroupByIndex(index: number, force?: boolean) {
		if (index >= this.groups.length) {
			return;
		}
		const oldActiveGroup = this.activeGroup;
		this.activeGroupIndex = index;
		if (force || oldActiveGroup !== this.activeGroup) {
			this.groups.forEach((g, i) => g.setVisible(i === this.activeGroupIndex));
			this._onDidChangeActiveGroup.fire(this.activeGroup);
			this._onDidChangeActiveInstance.fire(this.activeInstance);
		}
	}