src/vs/workbench/contrib/terminal/browser/terminalGroup.ts/TerminalGroup/focusPreviousPane
class TerminalGroup:	focusPreviousPane(): void {
		const newIndex = this._activeInstanceIndex === 0 ? this._terminalInstances.length - 1 : this._activeInstanceIndex - 1;
		this.setActiveInstanceByIndex(newIndex);
	}