Paggamit

Usage

• Reply and the add-on adds originals automatically — or asks first, if enabled in Options.
• De‑duplicated by filename; S/MIME and inline images are always skipped.
• Blacklisted attachments are also skipped (case‑insensitive glob patterns matching filenames, not paths). See Configuration.

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What happens on reply

• Detect reply → list original attachments → filter S/MIME + inline → optional confirm → add eligible files (skip duplicates).

Strict vs. relaxed pass: The add‑on first excludes S/MIME and inline parts. If nothing qualifies, it runs a relaxed pass that still excludes S/MIME/inline but tolerates more cases (see Code Details).

Part type	Strict pass	Relaxed pass
S/MIME signature file smime.p7s	Excluded	Excluded
S/MIME MIME types (application/pkcs7-*)	Excluded	Excluded
Inline image referenced by Content‑ID (image/*)	Excluded	Excluded
Attached email (message/rfc822) with a filename	Not added	May be added
Regular file attachment with a filename	May be added	May be added

Example: Some attachments might lack certain headers but are still regular files (not inline/S/MIME). If the strict pass finds none, the relaxed pass may accept those and attach them.

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Cross‑reference

• Forward is not modified by design (see Limitations below).
• For reasons an attachment might not be added, see “Why attachments might not be added”.

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Behavior Details

• Duplicate prevention: The add-on marks the compose tab as processed using a per‑tab session value and an in‑memory guard. It won’t add originals twice.
• Closing and reopening a compose window is treated as a new tab (i.e., a new attempt is allowed).
• Respect existing attachments: If the compose already contains some attachments, originals are still added exactly once, skipping filenames that already exist.
• Exclusions: S/MIME artifacts and inline images are ignored. If nothing qualifies on the first pass, a relaxed fallback re-checks non‑S/MIME parts.
  • Filenames: smime.p7s
  • MIME types: application/pkcs7-signature, application/x-pkcs7-signature, application/pkcs7-mime
  • Inline images: any image/* part referenced by Content‑ID in the message body
  • Attached emails (message/rfc822): treated as regular attachments if they have a filename; they may be added (subject to duplicate checks and blacklist).
• Blacklist warning (if enabled): When candidates are excluded by your blacklist, the add-on shows a small modal listing the affected files and the matching pattern(s). This warning also appears in cases where no attachments will be added because everything was excluded.

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Keyboard shortcuts

• Confirmation dialog: Y/J = Yes, N/Esc = No; Tab/Shift+Tab and Arrow keys cycle focus.
  • The “Default answer” in Configuration sets the initially focused button.
  • Enter triggers the focused button. Tab/Shift+Tab and arrows move focus for accessibility.

Keyboard Cheat Sheet

Keys	Action
Y / J	Confirm Yes
N / Esc	Confirm No
Enter	Activate focused button
Tab / Shift+Tab	Move focus forward/back
Arrow keys	Move focus between buttons
Default answer	Sets initial focus (Yes or No)

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Limitations

• Forward is not modified by this add-on (Reply and Reply all are supported).
• Very large attachments may be subject to Thunderbird or provider limits.
  • The add‑on does not chunk or compress files; it relies on Thunderbird’s normal attachment handling.
• Encrypted messages: S/MIME parts are intentionally excluded.

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Why attachments might not be added

• Inline images are ignored: parts referenced via Content‑ID in the message body are not added as files.
• S/MIME signature parts are excluded by design: filenames like smime.p7s and MIME types such as application/pkcs7-signature or application/pkcs7-mime are skipped.
• Blacklist patterns can filter candidates: see Configuration; matching is case‑insensitive and filename‑only.
• Duplicate filenames are not re‑added: if the compose already contains a file with the same normalized name, it is skipped.
• Non‑file parts or missing filenames: only file‑like parts with usable filenames are considered for adding.

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See also

• Configuration