This should not be confused with tapestry or designs where the entire chart is stitched as a 1/2 cross. For this, you should use the cross stitch tool but switch the display to show tapestry stitches.
The 1/2 stitch tool is used when a mixture of cross stitch and half cross stitch are required in the same design and it is desired to use the same symbol for a particular colour in both 1/2 cross and full cross.
The printed symbol chart uses two identical smaller symbols in opposite corners of the square.
Where it is required to show a single larger symbol, use the cross stitch tool but add the colour to the palette twice and allocate a different symbol for the 1/2 cross.
Screen display