I hear about the collection-type attribute for the first time and don't understand why we have to set it now if we didn't need to set it in oXygen 18.1 and used to get a proper result.
There were no changes between 18.1 and 19 regarding the way the navigation links ("the arrow icons next to the print icon above the topic title"
) are generated.
I have tested this scenario on my side with one of our sample DITA maps (flowers.ditamap) and if I removed the "collection-type" attributes set on the topicrefs I would get no navigation links in both 18.1 and 19. In my opinion this is the correct behavior.
Can you please transform again the same DITA map
(without the collection-type attribute being set) with both oXygen 18.1 and 19?
If in your case the 18.1 version of the output contains the navigation links and the other doesn't can you please send me a sample DITA map on which I can reproduce and further investigate the problem? In this case I will also need to know which distribution of DITA OT are you using: one of the DITA-OTs bundled with oXygen or an external one?
We use the default setting for webhelp.show.navigation.links, i. e. it is automatically set to "yes". But nothing happens.
The above parameter (if set to "yes") only enables the navigation links if the collection-type
attribute is set. The purpose of this parameter (if set to "no") is to allow disabling the navigation links and thus overriding the collection-type