Nothing happened when i drag n drop a grid component into empty block.. When i opened the console in developer mode i found error when drag the component into block like in video attachment.. Error message contains "Uncaught DOMException: Blocked a frame with origin "[domain name]" from accessing a cross-origin frame".. What's wrong about that and can you help me to fixing it.. Thank you..
Browser:

-Chrome Version 70.0.3538.110 (Official Build) (64-bit)
<div>-Firefox 64.0b14 (32-bit)</div>