Rated 5 out of 5 stars

Here are instructions to make this addon work with TB 68. . .


1. Unzip the .xpi file (change extension to .zip to extract natively, or use 7-Zip or other extractor).

2. In extracted root folder, create the file "manifest.json" in a text editor and populate as follows (first bracket to last bracket):

"manifest_version": 2,
"name": "Mark All Read Button",
"description": "Adds toolbar buttons to mark all emails or threads as read.",
"version": "0.7.2",
"applications": {
"gecko": {
"id": "{DA506923-55C4-4fbe-9E4C-D24B80D7DE9F}",
"strict_min_version": "68.0"
"author": "Mark S Baines",
"homepage_url": "http://www.linnhe.net/thunderbird/extensions.html",
"icons": {
"32": "chrome/skin/icon.png"
"legacy": {
"type": "xul"

3. Save the file. Note that the JSON syntax is *very* finicky, and so much as one misplaced punctuation mark may cause the addon not to load. Copy and overwrite this addon's info over a manifest from a working TB 68 addon if you run into trouble. (Note: this is a single-language manifest, since the original addon was not localized.)

4. Open "chrome.manifest" from the root folder in a text editor. Search and replace the following string (NOTE: -'s and +'s are for illustration only):
- style chrome://global/content/customizeToolbar.xul chrome://markallreadbutton/skin/markallreadbutton.css
+ style chrome://global/content/customizeToolbar.xul chrome://markallreadbutton/skin/markallreadbutton.css appversion<59.0a1
+ style chrome://messenger/content/customizeToolbar.xul chrome://markallreadbutton/skin/markallreadbutton.css appversion>=59.0a1

5. Save file.

6. ZIP up addon, keeping complete folder structure. Change .zip extension to .xpi.

7. Install in TB 68.


On casual test works like it always did, without triggering the Error Console. Note that most of this author's simple button addons hosted here and on his external website should be easily modifiable for TB 68 using this same method.

This review is for a previous version of the add-on (0.7.2).