Thats a great idea man, it happens accidentally I understand! A lock would be great.

Had moved a bunch of weapons to a second character. When I was cleaning up the inventory, dismantling guns, I thought I had my cursor on the second tier middle square. Leaving three greens to be dismantled before the legendary would shift to that spot. I held down the dismantle button, once one was done the next would move to the open space. I wasn't in the square I thought I was and the legendary popped into place before I had expected it to. I knew I screwed up when I saw ascendent energy pop up

That will learn ya