Composer crashes when forwarding with JAWS screen reader installed

[RealRaven2000]

This problem was observed by a user who is using the screen reader software JAWS, and needs to use keyboard navigation for Thunderbird.

When we use key commands to forward an Email with using the normal Account template and then use Tab to navigate from Subject line into the body of the email text, Thunderbird crashes hard without any warnings.

I believe JAWS does something unexpected when the composer editor gets focused that somehow interacts with the contents of the HTML container that displayes the editor.

[RealRaven2000]

doing a spot of debugging with JAWS this morning, I am getting intermittent crashes in the way described. I did some tests with removing signatures or images from the signature, but it doesn't seem to have much of an influence. I tried looking at focus events in the Thunderbird code itself but this is hard to debug as a breakpoint in the debugger steals focus away and thus it is not possible to test what happens in the next steps. It's also worrying that JAWS doesn't consider Thunderbird on the list of tested (supported) programs, see:

https://jfw.groups.io/g/main/topic/jaws_unstable/101179400

"...I've also noticed that in Thunderbird JAWS no longer read dialog titles. The list goes on and all Freedom Scientific will do is to tell me that that isn't a program they test JAWS with, end of support."

JAWS is hacking very deep into the OS and doesn't give much tools to debug it, so I am not hopeful that I will find a solution for this issue any time soon. I would highly recommend using a different screen reader program, in the meantime I can try to find an alternative way of editing forwarded mail.

[RealRaven2000]

After trying many things, the following workaround seems to work for me: in SmartTemplates settings, on the Global Settings page, disable the option "Insert Space to highlight %cursor%" in the Advanced functions group.

if you want to go to a certain place in the template to start editing you can still use the %cursor% variable within the template.

[RealRaven2000]

I did some tests with the latest version, it appears to be stable when "insert space to highlight %cursor%" is disabled:

smartTemplate-fx-4.10.2pre76.zip

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To try out this version, download the zip file and then drag it into Thunderbird Add-ons Manager (without extracting)
for users of screenreader you can also install this via the tools button after the "Find more addons" search text. activate the button with Enter then chose the 3rd menu entry "install addon from file...". Then select the zip file to install.

I intend to add an "enable accessibility features" checkbox at the top of General / Advanced functions, which will disable the "insert space to highlight" feature and possibly add more screenreader friendly functions in the future.