[BUG Report] 3D optimization output file deleted when...

I had a 3D opt output file it was read back into the 3D visualizer.

I just look around it and tried to close the file.

The Visualizer asked me whether to save or not.

I clicked no to leave the original file intact. I thought it would leave the original one because I didn't modify it at all.

BUT, it was completely deleted w/o asking me a word.

I just lost it and was so embarassed.

Shouldn't it leave the original output file as it was before if I didn't modify a thing at all?

confirmed.