So many reviews say they cannot work out how to use this addon because there's no documentation and it's not obvious. Me too. So, please, can someone who is using this successfully just spend a few minutes telling us how to use it? Surely that would make most of the (sometimes ungrateful) criticism go away.
One time, it worked for me (on Ubuntu 20.04 with TB 68.8.0). But only after I had found the config menu and deselected 'size' as a comparison criterion (having found this tip on the web). And only after I had given up then later found the output window in workspace #1 (I had launched the add-on from workspace #3).
But now, it seems to produce no output at all (I keep checking in all my workspaces). Does that mean that there's no duplicates, or that it isn't working? Please try to document this for someone who doesn't know what is meant to happen because they have never used it before.
Like others, I don't know the significance of the menu "Set original message folder(s) for next duplicate search". I suspect I'm meant to use this to select one folder, then right click on 'Remove Duplicates...' in any other folder (or the same folder). But, given the addon no longer gives me any output, I cannot test this theory.
The one time it worked, it was fast and useful...