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		This is just a guess but the four lines in a rectangle, created by using the rectangle tool, may be treated as a single element. You could try exploding the rectangle.
  In AutoCAD LT a rectangle created using the rectangle tool did act as a single element, or like a block, as I recall. If you didn't explode it and tried to erase one of the sides the whole rectangle would be erased.
  Trikester
	
	
	
	 
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