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  1. Moodle
  2. MDL-69292

Atto performance issues (lock-ups) in Safari in Moodle 3.8, 3.9



    • Type: Bug
    • Status: Waiting for peer review
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: 3.8.4, 3.9.1
    • Fix Version/s: None
    • Component/s: HTML Editor (Atto)
    • Labels:


      We just upgraded to Moodle 3.8, and we're seeing some rather major performance issues with the Atto editor when using the Safari browser. We also see this on 3.9 (using sandbox.moodledemo.net). 

      What we're seeing is unresponsiveness and lock-ups in Atto when using Safari. For example, when writing on a page, selecting some text, the selecting the Heading toolbar icon, we see a stutter in how Atto reacts. Oftentimes, one has to wait a second or two for the change to take place. This sluggishness seems to be especially prevalent when using the Font Color toolbar. Selecting text, then selecting a color, one usually has to wait a couple seconds for the change to take place. And then, you usually can't do anything in the browser for a couple seconds or more, until it unfreezes and returns you control.

      What follows are the steps to reproduce in Safari, and I've attached stack trace results that Safari gave.

      Steps to reproduce:
      Visit https://sandbox.moodledemo.net/
      Login as: `teacher` / `sandbox`
      Click `My First Course`
      Click `Turn Editing On`
      Click `Add activity or resource`
      Click `Page`
      In the Atto Toolbar for the description field choose `A` (Paragraph Styles)
      Pick any style
      (See attachment for stack trace results).


      We are also seeing these results in Chrome (Mac), where we are seeing some lock ups (e.g., the second or third heading change triggers it and locks up for a moment. However, once the initial lock up is done the error still shows up, but performance seems fine.) But there appears to be less impact on performance in Chrome. We don't see these problems at all when using FireFox ( Mac). 

      These issues are not present at all in Moodle 3.7. They appear to have been introduced in Moodle 3.8.

      Please let me know if any of this isn't clear or if there is more information we can provide that would be helpful. 

      Thanks... Brian





            bnwinsf Brian Warling
            Component watchers:
            Andrew Nicols, Jun Pataleta, Michael Hawkins, Shamim Rezaie, Simey Lameze
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