Rated 5 out of 5 stars

it is similar to XNote++ add on (<a class="linkification-ext" href="https://addons.mozilla.org/en-us/thunderbird/addon/xnotepp/" title="Linkification: https://addons.mozilla.org/en-us/thunderbird/addon/xnotepp/">https://addons.mozilla.org/en-us/thunderbird/addon/xnotepp/</a>) but with search capabilities.

Vantage point: Search among notes

Minor problems: Bad icon in message toolbar (TB 3.1)

Suggestions for further improvement
1. keyboard Shortcut (and button in message toolbar) for deleting notes (with confirmation if user wants it)
2. Search results be all presented in a column (in new tab) like the way thunderbird filters messages.
3. Easily create and attach one note to a lot of messages. (Presently it is cumbersome to add the same note to many messages )
4. Easily delete notes from many messages by marking the messages and then click the "delete notes from messages" option or a "delete notes" button in message toolbar.
5. A new tag in thunderbird to tag messages having a note

overall, a useful and very much needed add on

Giorgos

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Update after Developer's reply:
I followed the steps provided by the developer (congrats for the immediate and detailed reply) and successfully changed the icon in message toolbar. My tag suggestion has to do with an option to auto tag (under the same tag and without manual user intervention) all emails that have messages.

This review is for a previous version of the add-on (1.2.2.9). 

thanks for the review and some questions

Thank you for the high quality review.

> Minor problems: Bad icon in message toolbar (TB 3.1)
Actually you may replace it yourself. Locate file messagenotesplus.jar. It may look something like c:\Users\alex\AppData\Roaming\Thunderbird\Profiles\ydrahk2q\extensions\messagenotesplus@mozilla.org\chrome\messagenotesplus.jar. It is actually zip archive. Unpack it. Find skin\note_icon_grey.png there and replace it by picture you like. Then pack the archive back. Of course the names of the files should remain the same.
Also if you have ideas about the icon please give me the link to the image I will use that in next version.

> 5. A new tag in thunderbird to tag messages having a note
Well, I use TB 3.1 myself. And as far as I can see user can create any custom tags. What do you mean exactly?

I will take all your suggestions in mind for next version. Especially ability to attach notes.