Error message `TypeError: config.browser is null` shows up when using Muttator and Lightning calendar extension

[kkremitzki]

Issue type:

• Bug report

Version:

Muttator:   1.3 (created: 2016/07/29 19:24:17)
Thunderbird:    Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0

Description:

When using the Lightning calendar extension (version 4.7, most recent version compatible with Thunderbird 45) with Muttator, after clicking the 'Switch to the calendar tab' button, an error message in the command line/Liberator statusline either immediately, or after trying to interact with Muttator (e.g. pressing : (colon)). Error message: TypeError: config.browser is null

This error was also reported in the reviews for the Muttator addon here: https://addons.mozilla.org/en-US/thunderbird/addon/muttator/reviews/765475/

Besides the error message popping up, Muttator's mappings (e.g. gt, gT) no longer work.

Expected behavior:

1. Error message does not pop up.
2. Able to continue using applicable Muttator mappings like gt, gT
3. Able to interact with calendar, ideally.

Steps to reproduce:

1. Install Thunderbird 45 (installed on Ubuntu 16.04 from repositories here)
2. Install Lightning addon version 4.7
3. Install Muttator 1.3
4. Restart Thunderbird if necessary to activate all extensions and then click on 'Switch to the calendar tab' button
5. Press :. If the calendar tab is active, the error will occur. If other tabs are active, the normal behavior (i.e. command line shows up) will occur.

[kchr]

Seems to be reproducible in Thunderbird 52.5.0 as well, using the native Lightning intergration (version 5.4.5).