IMHO, Git only supports "Prune obsolete worktrees" which already exists as a menu item.
But it (SmartGit) could also `rm -rf` the directory, right?
But it would be tricky, because there could be other obsolete worktrees, too, that silently could be deleted, too.
Then maybe a separate menu "Delete worktree" that only deleted the files on the disk, and then prune removes it from git?
Because it's weird to have to switch to another app (Finder) to do a part of the feature (Worktrees) while being able to do other parts directly in SmartGit.
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