Rated 5 out of 5 stars

Thanks for your effort and the quick fix !

This review is for a previous version of the add-on (2.2.10). 

Please don't use this page for bug reports - see http://www.froihofer.net/xnote/

With that piece of information, I can't do anything. Please give more details on what you did and your system environment. Check your Thunderbird profile directory for the XNote folder. It should contain all your notes stored in files. If you installed Thunderbird on a new PC, you need to copy the files from your old PC. Are you using a different profile for TB45?

Note on solution: Problem seems to be a change in add-on initialization with TB45 so that e.g. ImageZoom (this case) now overrides the XNote initialization. Will be fixed in 2.2.11. For those who cannot wait, you may want to try version 2.2.11a: https://addons.mozilla.org/en-US/thunderbird/addon/xnotepp/versions/2.2.11a - Note that this moves you to the channel for beta updates so that you will need to install the final version 2.2.11 manually after its released in order to get back to the channel for release updates.