bookmark (left navigation pane) comes as expanded by default on PDF report docbook 1.74.3

Hi,

 

I am using docbook version 1.74.3. to generate PDF reports.

I have left navigation pane (bookmark) on the report.

 

This left navigation pane shows all the section and chapter already expanded when the report is genereted.

How can I make it to generete report so that all the sections comes as collapsed by default?

 

Thanks,

Bela.