src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/TerminalGroup/setVisible
class TerminalGroup:	setVisible(visible: boolean): void {
		if (this._groupElement) {
			this._groupElement.style.display = visible ? '' : 'none';
		}
		this.terminalInstances.forEach(i => i.setVisible(visible));
	}