FOUND IT!!
public override void PositionEditingControl(bool setLocation, bool setSize, System.Drawing.Rectangle cellBounds, System.Drawing.Rectangle cellClip, DataGridViewCellStyle cellStyle, bool singleVerticalBorderAdded, bool singleHorizontalBorderAdded, bool isFirstDisplayedColumn, bool isFirstDisplayedRow)
{
cellBounds = new System.Drawing.Rectangle(cellBounds.X, cellBounds.Y, cellBounds.Width + 16, cellBounds.Height);
cellClip = new System.Drawing.Rectangle(cellClip.X, cellClip.Y, cellClip.Width + 16, cellClip.Height);
base.PositionEditingControl(true, true, cellBounds, cellClip, cellStyle, singleVerticalBorderAdded, singleHorizontalBorderAdded, isFirstDisplayedColumn, isFirstDisplayedRow);
}