Either new feature or help if it exists already

[gdssjov]

Problem:
i.e. 5000 dub files.
Warning - all in each group marked for deletion - i.e 300 groups.

How do I select to keep all but one in each group - but only the 300 groups - not all the 5000 ?
If not possible, its a feature suggestion
regards
Ulrik

[DigitalVolcano]

You can click on the option 'Work only on currently selected rows' in the Selection Assistant. Then select (not mark) the files in your 300 groups, then use the 'Select by group->All but one in each group' command.

'Group has all Marked' filter may help with this (Duplicate Cleaner Pro).