709532 - Today Pane flashes/flickers every time calendars are reloaded

Status: NEW

(Calendar :: Calendar Frontend, defect)

Description

[Joris Debonnet]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0.1) Gecko/20100101 Firefox/8.0.1
Build ID: 20111120135848

Steps to reproduce:

I use Provider for Google Calendar 0.9, by the way. 
I always use Thunderbird with the Today Pane open, and am often reading a long email in Preview. 


Actual results:

While concentrated on the email I am reading, I see something happen on the Today Pane. So I look over there to see what's up, but nothing changed. It happens because for some reason the events disappear and simply reappear a second later. This happens every 10 minutes I think. It might be 15 or 20 but it's certainly the same period every time. 


Expected results:

Even if the events or view is updated, it should leave the previous version rendered until all new information is available, and only then replace it. All in all, I don't want to be distracted if there is no reason for it. The Today Pane should not 'flash up' if there's no change.

Comment 1

[Felix Möller]

Sadly this is a known issue.

Comment 2

[Pete Riley]

I'm not sure this is a dupe of bug 466742.

The today pane erases and redraws everything every time remote calendars are refreshed (maybe only when they've changed).

You have some control over this by double clicking each remote calendar in the calendar list and tell them to only refresh every hour.  Unfortunately you can't specify more than an hour because it uses a dropdown instead of a field where you can type in N minutes.

I agree that the way the today pane redraws itself is distracting.

Comment 3

[Martin Schröder [:mschroeder]]

I agree with Pete in comment#2. De-duplicating this bug report.

Comment 4

[Merike Sell (:merike)]

Attachment: cal-refresh-movearound

I initially thought that it might be a good idea to keep track if any of the visible items have actually changed and only reload UI when so. But then I noticed only moving around item removal a bit made visible flicker disappear on my setup. I don't exactly understand why this is so and this approach might not be correct.

Putting this up for review to find out if it should or should not be done this way and if not what might be a better way. Got tired of flickering :)

Comment 5

[Martin Schröder [:mschroeder]]

(In reply to Merike Sell (:merike) from comment #4)
> Created attachment 8891691 [details] [diff] [review]
> cal-refresh-movearound

The moved code is never called because the function bails out in the if statement before, which is the same as in the moved code.

Comment 6

[Merike Sell (:merike)]

Duh, obviously. I'll need to do more reading to understand some of the questions this triggered.

Comment 7

[Vladimir Panteleev]

It flickers even when you have only one calendar and the HTTP server replies with "304 Not Modified". (So, Thunderbird knows that nothing changed, and it still repaints everything causing flicker.)