You can put an editbox in that column.

Open the property sheet in the form designer. Select the column at the top of the property sheet. Click the editbox control on the form controls toolbar then click the grid. In the property sheet there should be the editbox under the column. Set the column currentcontrol property to the editbox. Set the column sparse property to .F. and make sure the rowheight of the grid is tall enough to display the font.

The other way, which I prefer, is to have an editbox directly underneath the grid to display the memo and refresh it whenever the record pointer is moved.