Try this:
(1) Select more than one cell
(2) Over this selection hold down the mouse key.
(3) You are able to drag the cell range

Now try this:
(1) Select more than one cell
(2) Type some numbers/characters
(3) Type ALT+ENTER
(4) The numbers/characters you have given, are inserted in each of the selected
cells.
(5) Over the still selected cell range hold down the mouse key.
(6) You are NOT able to drag the cell range