Fuel tank won't drag when clicked on

I grabbed a section of a fuel tank to alter its length, then went to attatch it back in line with the rest of the stage. The fuel tank initially snapped to the side of the stage, then the game froze briefly. After the game unfroze the tank was stuck to the side of the tank. I hit undo and the game reverted to before i removed the tank from the stage. Now when I click and drag on the fuel tank to remove it it is stuck in place and the camera only rotates

Edit: Simplified version of this craft here that demonstrates the issue is here.