> 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.

You are absolutely right. When doing filtering, entries shown or not shown have not much to do with the filter. 
Rather than messing around with first and last entries, I decided to break apart threads completely when doing 
filtering, so the entries are treated as individual entries, just like what you do when filtering in summary mode. 
This gives then consistent filtering results. The modification is done in revision 2282.