This is a common bug I have when using studio, and I found a method which will give you the bug I am having. It can be fixed easily by pressing Play and Stop again.
Open a new place
Press ‘Play’ in the Home tab.
When you spawn in, navigate to explorer, find your robloxian, and press CTRL + C.
Press ‘Stop’.
When you press Stop you will see that the explorer tab turned completely white. As mentioned above, an easy way to fix it is to just press Play and Stop.
This has been a thing for months, but usually both the properties and explorer windows are both white. The fix is to go to the “Start Page” tab you see up there and then go back to your place, and it will show the contents of the explorer/properties again.