I am using TextAreaCache but it is on Pale Moon.It is definately a time-saver.
I can suggest this add-on to replace TextAreaCache and Lazarus: Form History Control
It saves all form and text area entries although it is not as convenient as others mentioned.(Confirmed myself it is working on FF v.44)
Alternatively, you can look for more options in this add-ons collections: For Filling & Saving Form Data :: Collections :: Add-ons for Firefox
Also, I would suggest you report this bug on the add-ons/developer's website so it may be fixed.
Hope that helps you.
I am using Text area cache but it is on Pale Moon. I can suggest this add-on to replace TextAreaCache and Lazarus: Form History Control
It saves all form and text area entries although it is not as convenient as others mentioned.(Confirmed myself it is working on FF v.44)
Alternatively, you can look for more options in this add-ons collections: For Filling & Saving Form Data :: Collections :: Add-ons for Firefox
Hope that helps you.