src/vs/workbench/browser/parts/views/viewPane.ts/ViewWelcomeController/onDidChangeContext
class ViewWelcomeController:	private onDidChangeContext(): void {
		let didChange = false;

		for (const item of this.items) {
			if (!item.descriptor.when || item.descriptor.when === 'default') {
				continue;
			}

			const visible = this.contextKeyService.contextMatchesRules(item.descriptor.when);

			if (item.visible === visible) {
				continue;
			}

			item.visible = visible;
			didChange = true;
		}

		if (didChange) {
			this._onDidChange.fire();
		}
	}