thunar 4.20: double click to activate items via touchpad double tap not working (was fine in 4.18)

Version information

4.20.0 Devuan unstable (based on Debian unstable)

Steps to reproduce

1. Have "Double click to activate items" activated in Thunar 4.18.11 and notice that working fine with touchpad double tap
2. Upgrade thunar (alongside thunar-data and libthunarx-3-0) to 4.20.0 and notice that the item gets selected, but not activated
3. Downgrade thunar (alongside thunar-data and libthunarx-3-0) to 4.18.11 and notice that items get properly activated with double tap.

Current behavior

In Thunar 4.20 a touchpad double tap seems to have the effect of a single click, while in 4.18 it had the effect of a double click.

Expected outcome

"Double click to activate items" should again work with touchpads, like in 4.18.

Additional information

In xinput, the touchpad double tap creates the same sequence as a mouse double click:

button press   1 
button release 1 
button press   1 
button release 1 

The problem is isolated to Thunar and does not occur in other Xfce 4.20 components. In xfdesktop4 the double click via touchpad double tap on the desktop works in 4.20 just as fine as it did in 4.18.

Edit: The issue only affects List View, not Icon View or Compact View.