Tablature preview needs to show two voices
Right click on a tablature staff. Select Advanced style > Note values. Set "Shown as" to "Stems and Beams," Set "Stem style" to "Beside staff" and "Stem position" to "above."
The preview pane only displays voice 1 stems and beams. Could this be replaced with a better example in two voices for the guitar, which shows the above- and below-staff orientation of stems.