Launch host app from watch app

I know that the openParentApplication api in watch kit extension can open the host app in the background but not in the foreground.

I also tried using openUrl() api of NSExtensionContext as below:

NSExtensionContext *ctx = [[NSExtensionContext alloc] init];

NSURL *url = [NSURL URLWithString:@"myScheme://today"];
[ctx openURL:url completionHandler:^(BOOL success) {
    NSLog(@"fun=%s after completion. success=%d", __func__, success);
}];
[ctx completeRequestReturningItems:ctx.inputItems completionHandler:nil];

Here too the host app is not launched. Am I missing something? or is it not possible to launch the host app from watch kit extension?