1784889 - Thunderbird 102 calendar does not show all calendar events

Status: RESOLVED DUPLICATE of bug 1789437

(Calendar :: General, defect, P2)

Description

[Rainer]

Attachment: Calendar screenshots.jpg

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0

Steps to reproduce:

I updated from TB 91 to TB 102 and opened the calendar view.

Actual results:

A calendar that was previously displayed completely now misses some calendar events. I attach two screenshots, one of Thunderbird 91.12.0 (calendar complete) and one of Thunderbird 102.1.2 (calendar incomplete), both under Windows 11. They both show the exact same week of the exact same calendar configured with the exact same options.

Some details:

• The calendar is a remote calendar hosted by Kolab Now (https://kolabnow.com/). I have used it on a daily basis for a long time, and it worked well within Thunderbird until version 91.x.
• I tested the difference again on a new computer (Windows 11), where I did a fresh install of TB 91.12.0 with a new profile, then deleted it completely including the profile, and then did a fresh install of TB 102.1.2 with a new profile. This is where the screenshots are from.
• First I thought that only recurring events are missing, but then I saw that it’s across the board. I see no particular pattern.
• I can find the missing events when I use the calendar search function. So it seems that they are synchronized with the server but not properly processed/displayed.

I use this calendar for my business. So this is not just a minor inconvenience. It made the TB calendar practically unusable overnight.

Expected results:

The calendar should have been displayed completely.

Comment 1

[Rainer]

Comment on attachment 9289889 [details]
Calendar screenshots.jpg

Same calendar viewed in different TB versions.

Comment 2

[Thomas D. (:thomas8)]

Thanks Rainer for letting us know. That shouldn't happen. As you say, somehow the events are still around (as seen from TB calendar search) but not displayed, so user does not have access. Which is (perceived) dataloss.

Would you be able to do the following?

• Create a new calendar on KolabNow, and make it public.
• Put various events similar to those which you have in the broken calendar.
• See if they all display in Thunderbird.
• If not, share the link to the calendar with us here.
• Have you created the affected/non-affected events using different tools like Thunderbird and Kolab?

Comment 3

[Paddy]

I'm having the same issue, except with my remote calendar hosted on Google Calendar rather than KolabNow. Some events from specific calenders are missing. For example, I have one with birthdays & anniversaries; it shows a few birthdays and not others, with no obvious difference between each entry (other than the date and title of the entry, of course).

Not sure how helpful this comment was but just thought it might be good to mention that it's probably not a server-side issue with KolabNow!

Cheers.

Comment 4

[Rix99]

This is similar to Bug 1790340 I reported

Comment 5

[Magnus Melin [:mkmelin]]

For referencing bugs, please just write "bug XXX" so bugzilla can autolink.

Comment 6

[luniac]

I can confirm this. As a temporary workaround, you can go to each calendar's properties and disable offline support (click ok/exit), then re-enable offline support. This will restore the events - for how long, who knows?

This is basically what kills a product and I don't think thunderbird can be trusted with the important role of managing calendars any more.

Comment 7

[Rainer]

(In reply to Thomas D. (:thomas8) from comment #2)

Thanks Rainer for letting us know. That shouldn't happen. As you say, somehow the events are still around (as seen from TB calendar search) but not displayed, so user does not have access. Which is (perceived) dataloss.

Would you be able to do the following?

• Create a new calendar on KolabNow, and make it public.
• Put various events similar to those which you have in the broken calendar.
• See if they all display in Thunderbird.
• If not, share the link to the calendar with us here.
• Have you created the affected/non-affected events using different tools like Thunderbird and Kolab?

Sorry for not replying earlier. I had tried to create a public calendar on Kolab Now but failed. Even when I gave everyone access, the calendar still required (my) password to be readable from outside. This looks like a Kolab Now bug on its own. I suggest you reach out to [e-mail].
As I can see from the other posts here, however, this is not only a Kolab Now issue but turns up in different email services.
Other things that I found out in the meantime:

• luniac's workaround does not work for me. It does not restore the events.
• Most but not all of the missing events are recurring events. They were created both in Kolab Now and Thunderbird.
• When I export the Calendar as an ics file through the Kolab Now web interface and import it into a local Thunderbird calendar, some of the missing events show up, but others are still not diplayed (but can again still be found in the search function).
• When I import the ics file in Thunderbird into a subscribed remote calendar with another email provider (which then synchronizes the events to another server), the events not displayed do not get transferred there at all.
• The error console shows lots of instances of:

 Error: Same occurrence found twice, protecting you from death by recursion Ical.jsm:7319:15
    icalrecur_iterator_next resource:///modules/calendar/Ical.jsm:7319
    getOccurrences resource:///components/calRecurrenceRule.js:105
    calculateDates resource:///modules/CalRecurrenceInfo.jsm:548
    getOccurrences resource:///modules/CalRecurrenceInfo.jsm:637
    _expandOccurrences resource:///modules/calendar/CalStorageItemModel.jsm:335
    start resource:///modules/calendar/CalStorageItemModel.jsm:201
    InterpretGeneratorResume self-hosted:1422
    AsyncFunctionNext self-hosted:632

Not sure if this is related, but might be helpful.

• The latest Outlook version (+ CalDav Synchronizer) displays the same calendar flawlessly, just as the Apple Calendar on iPhone and iPad,

Comment 8

[Magnus Melin [:mkmelin]]

Sounds like bug 1789437