[frontend] Freeze on task edit

[tbarbette]

Describe the bug Sometimes, clicking on "Appliquer les changements" when editing a task leads to a browser freeze.

INGInious installation details

• Version: 0.8.6 (UCL)
• Containers version (if applicable) [e.g. the git hash]

To Reproduce It is not 100% reproducible.

• Edit a task (for UCL, this is the one with the problem https://inginious.info.ucl.ac.be/course/LINFO2241/project-3-submission)
• lose the focus of the window, then come back
• click on submit change
• The tab completely freezes. On Edge one can still scroll but hints show the backend is frozen (the cursor display as a hand for instance)

Note: It particularly happens if I submit a file in a second tab, and then go back to edit the task and hit "submit".

Expected behavior The browser does not freeze :)

Screenshots Profiling of the page in Chrome: A problem I saw in the console (not always I think):

Desktop (please complete the following information):

• OS: Windows
• Browser Both Chrome and Edge (-> WebKit)
• Version Chrome 119, Edge latest public release :)

Additional context Anthony identified the source as potentially

    // Open file selector on div click
    $(".upload-area").click(function(){
        $("#file").click();
    });

This is in line with the profiling screenshot shown above.