java – Why can I not open the desktop and core folders in libGDX?

I think the problem is caused beacuse I have two JDK’s. One dedicated one and another integrated from Android Studio. Before, when I start the bulid it gave me a warning:

[options] bootstrap class path not set in conjunction with -source 1.6

There is only one search I found online that did not help me.

But I can no longer reproduce this.
Can anyone help me? I dont know what I am doing wrong.
I cannot run the project, nor browse the folders in Android Studio.

Here is a screenshot:
Problem