Gantt multiselect selection bug

When activate multiselect plugin (multiselect: true) and set multiselect_one_level: true then there is issue with single selection in different levels.

Example structure:
1. Parent Task (parent1)
a. Child Task (child1)

Then if I click on child1 then it gets selected. After that I click on parent1 to select it, but there is just child1 deselected. I have to click one more time to select parent1. (this issue is in both directions parent > child, child > parent)

I have this listener there:

This event is called for each task and there is passed state: true if the task is going to be selected, false - if unselected

for child1 it is false which is correct
for parent1 it is true which is correct too - but task is not selected

here is example:

Hello David,
Thank you for providing a more detailed explanation and the snippet. But please, don’t ask the same questions in different places.
I answered you there: