Rated 5 out of 5 stars
If your QuickText won't work any more, you should upgrade to this latest version 0.9.11.7 dated May 24, 2016. This version gets QuickText to work again in Thunderbird 52.6.0 (32 bit) - but there are a few cautions:
(1) BEFORE you install this latest version of QuickText, export your templates to a safe place because you MIGHT need them again.
(2) Install the newest QuickText into Thunderbird (do NOT uninstall your existing QuickText).
(3) This is where it got kinky for me. After restarting TBird, QuickText was nowhere to be seen and was not listed as installed in Add-Ons. So I installed the new QuickText again and restarted TBird.
(4) Amazingly, QuickText was now back and all my templates were there again. With any luck you can now add templates (I haven't tried that yet) and they will be remembered.
If your templates are gone, you might try importing that back up copy I suggested making at the beginning. Also, please note that your QuickText templates are stored in your TBird Profile in a folder called "QuickText". The folder was in my My_Mail folder.
Latest quicktext works with TB52 and TB60 again.