Bug 8054 - Error message when resizing text area
Summary: Error message when resizing text area
Status: NEW
Alias: None
Product: ThinLinc
Classification: Unclassified
Component: Web Access (show other bugs)
Version: trunk
Hardware: PC Unknown
: P2 Normal
Target Milestone: LowPrio
Assignee: Bugzilla mail exporter
Keywords: prosaic
Depends on:
Reported: 2022-12-20 10:09 CET by Fredrik
Modified: 2023-04-25 12:35 CEST (History)
2 users (show)

See Also:
Acceptance Criteria:

Firefox with always show scrollbar and resizing error. (186.12 KB, image/png)
2022-12-20 10:09 CET, Fredrik
chrome error message (452.46 KB, image/png)
2022-12-20 13:57 CET, Fredrik

Description Fredrik cendio 2022-12-20 10:09:03 CET
Created attachment 1101 [details]
Firefox with always show scrollbar and resizing error.

When resizing the textarea with speed, it throws out this error message and lock the session.

To reproduce this error message:

1. Languagetool extension enable, and Firefox settings turn on Always show scrollbars.

2. Go to clipboard and focus on the textarea

3. Resize the textarea fast.
Comment 1 Fredrik cendio 2022-12-20 13:54:46 CET
This has been spotted on Windows without the Firefox settings, and this because it already has the "always show scrollbars". 

The same issue have can be reproduced in chrome and edge browsers, but it's lot harder to reproduce.
Here is a thread on resize-observer GitHub.
Comment 2 Fredrik cendio 2022-12-20 13:57:15 CET
Created attachment 1102 [details]
chrome error message
Comment 3 Samuel Mannehed cendio 2023-03-31 15:46:36 CEST
After commmit r39902, for bug 7909, this can no longer be reproduced. That commit added a 0.2s transition to all properties of textareas. This seems to prevent the crash.
Comment 4 Samuel Mannehed cendio 2023-03-31 15:59:59 CEST
To test this, I did the following:

 1. Enabled “Always show scrollbars” in Firefox settings
 2. Opened Language Tool extension settings and enabled LT for private tabs
 3. Opened Web Access and connected in a new private tab
 4. Opened the inspector for the clipboard textarea and disabled the transition-property
 5. Got the crash

If I then either disabled LT or re-enabled the transition-property, I could no longer get the crash.

Note that Web Admin doesn't crash or log anything regarding such issues when doing the above procedure regarding any of the Web Admin textareas.

But since the crash was related to LT, and no longer occurs in the current state of things, I see no reason to keep this around.
Comment 5 Frida cendio 2023-04-04 09:03:02 CEST
Tested this as described in comment #4. I get the crash when the transition is turned off, and I did not manage to get the crash with the transition in place. So, I consider this fixed.
Comment 6 Frida cendio 2023-04-04 14:57:05 CEST
Tested this again, and now I get the crash even with the changes mentioned in comment #3. I am not sure what I did differently this time, but I found one thing that I did now that I'm not sure if I did before. This is to click in the text area to activate LanguageTool before resizing it. I also found that resizing vertically will trigger the crash more often for some reason.
Comment 7 Frida cendio 2023-04-04 15:38:06 CEST
The ResizeObserver mentioned in the error message is not ours. The only ResizeObserver we create in our code is for the framebuffer window. So, I would say that this bug is not about fixing the error, but rather about handling the error better and not freezing the session.
Comment 8 Frida cendio 2023-04-11 12:41:44 CEST
There is a workaround in place in noVNC, at least for firefox.


In edge and chrome you get this instead:
> ResizeObserver loop limit exceeded

Since this only appears to happen when languagetool is active, I reported an issue to them. We have to see what happens with this.

Comment 9 Samuel Mannehed cendio 2023-04-25 12:35:51 CEST
Note that the change that made this more difficult to reproduce (part of r39902) was reverted in r40079.

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