You can click on any of the EG graphs to change the key up position for all of the graphs. This doesn't affect the TX81Z at all. The key up line represents how long you hold the key down, so it varies with each note played. The release rate kicks in when you release the key, so this is how I have depicted it on the graph.
The scroll bar over the EG graphs will scroll all of them so you can more or less see everything.
You can hide the labels and arcs by checking the Hide EG Labels option in the Options menu of the voice editor.