src/vs/workbench/browser/parts/compositeBar.ts/CompositeBar/resetActiveComposite
class CompositeBar:	private resetActiveComposite(compositeId: string) {
		const defaultCompositeId = this.options.getDefaultCompositeId();

		// Case: composite is not the active one or the active one is a different one
		// Solv: we do nothing
		if (!this.model.activeItem || this.model.activeItem.id !== compositeId) {
			return;
		}

		// Deactivate itself
		this.deactivateComposite(compositeId);

		// Case: composite is not the default composite and default composite is still showing
		// Solv: we open the default composite
		if (defaultCompositeId !== compositeId && this.isPinned(defaultCompositeId)) {
			this.options.openComposite(defaultCompositeId);
		}

		// Case: we closed the last visible composite
		// Solv: we hide the part
		else if (this.visibleComposites.length === 0) {
			this.options.hidePart();
		}

		// Case: we closed the default composite
		// Solv: we open the next visible composite from top
		else {
			this.options.openComposite(this.visibleComposites.filter(cid => cid !== compositeId)[0]);
		}
	}