src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/TerminalGroup/attachToElement
class TerminalGroup:	attachToElement(element: HTMLElement): void {
		this._container = element;

		// If we already have a group element, we can reparent it
		if (!this._groupElement) {
			this._groupElement = document.createElement('div');
			this._groupElement.classList.add('terminal-group');
		}

		this._container.appendChild(this._groupElement);
		if (!this._splitPaneContainer) {
			this._panelPosition = this._layoutService.getPanelPosition();
			this._terminalLocation = this._viewDescriptorService.getViewLocationById(TERMINAL_VIEW_ID)!;
			const orientation = this._terminalLocation === ViewContainerLocation.Panel && this._panelPosition === Position.BOTTOM ? Orientation.HORIZONTAL : Orientation.VERTICAL;
			this._splitPaneContainer = this._instantiationService.createInstance(SplitPaneContainer, this._groupElement, orientation);
			this.terminalInstances.forEach(instance => this._splitPaneContainer!.split(instance, this._activeInstanceIndex + 1));
			if (this._initialRelativeSizes) {
				this.resizePanes(this._initialRelativeSizes);
				this._initialRelativeSizes = undefined;
			}
		}
		this.setVisible(this._isVisible);
	}