I thought i was going crazy. Many times when I use the MOVE command, what i want to do is move the entity relative to its current position, and suddenly it seemed the feature was not working properly at all. I was marking up some DWG files of plastic enclosures made by several manufacturers to show where I needed holes drilled and cutouts made. So typically I would pick an entity to move and select "D", meaning "Displacement, and then I'd specify an X,Y displacement.  I was using INCHES for my units system, so if I type 0,1, I expect to see the entity mover 1 inch to the right  no vertical movement. Instead it seemed entity moved by some seemingly random amount, often well outside the drawing bounds. This displacement behavior was useless.Initially i got around it by setting a new CSS origin exactly at my "key" reference point on the entity, and then doing an absolute move. But the actual solution to the problem turned out to be in the drawing settings.

I already knew from the tutorials to check and set my Unit System and drawing bounds, which was good because a lot of DWG files these manufacturers supply would have "Unitless" in Drawing Settings->Unit System->Block Units Format, which I always set to INCHES, since that was my reference.  But the real culprit was in the coordinate system! Invariably in every DWG file that had this problem with faulty MOVE->DISPLACEMENT behavior, I'd find Drawing Settings->Coordinate System->Named set to "Unnamed". As soon as I set this to "WORLD" and clicked "ACTIVATE", the problem was eradicated.

I'm sure to many experts the above is pretty obvious, and even for a newbie like me this would never be an issue starting your own drawings within DS. But if you run into this problem and it was NOT a drawing you know was made with DS, Check that coordinate setting! It just might save you some major frustration! :-)