Mouse modifier "Track/double click" doesn't work below last track

[heda]

this must be a bug
using v5.973

mouse modifier "Track/double click" doesn't work on area bellow last track, while single click does.
here I test how single click works on tracks and on area below tracks, and then testing double click when clicked below last track doesn't start playing as I have configured it to do.

[heda]

additionally... I think what it happens is that both Left click and double click actions are being executed when double clicking except in the area below last track where only left click action is executed.
So fixing to execute only the double click action in both cases would be the best.
This also happens for double clicking with Shift CTrl Alt etc modifiers.