Hello,
   I feel that the filter result could be confusing and unexpected when "COLLAPSE TO LAST" is enabled: you 
filter the first entry but you show the last one. What is filtered doesn't correspond with what is shown (look 
the attached example). 

I suggest to implement an option to let the user decide which entry (first or last) should be retrieved for 
filtering (a tentative patch is attached).

Thank you 

    Gabriele

P.S. A similar behaviour occurs when you sort the logbook: it could appear as not sorted because you sort the 
first entry but the last one is shown.