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Firefox support for Monaco editors

Feature Requests

Parts of the spacelift UI that embed the Monaco editor do not work on firefox, due to a minor bug in the way that the embed wrapper checks the OS, in order to format the aria strings.

Workaround
Problem
Status: ❌ Rejected4 comments

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Comments4

  • Aleksandra Cieslak

    Team•

    Jul 29

    Hi, thanks for the detailed report.

    We've looked into this, and fixing Firefox compatibility here would take more effort on our end than the fix might suggest at first glance, and it's not something we can prioritize right now given how few of our users are on Firefox.

    For now, the recommended path is to use a different browser when working with the Monaco editor. I'm closing this request, but if Firefox usage becomes more significant for our customer base, we'll revisit.

  • Gray Tomato

    •

    Jul 17, 2025

    OS is Windows 11 23H2, build 22631.5624

    Browser is Firefox Developer Edition 141.0b9 (64 bit)

    I have also reproduced it on macOS Sequoia 15.5, with Firefox 140.0.4 (aarch64)

    From my research I believe this is the intended behavior of this property on Firefox and should happen on any platform (https://bugzilla.mozilla.org/show_bug.cgi?id=1750143, https://github.com/mozilla/standards-positions/pull/579)

    There’s more than 1 location where it happens, but the first place I observed it is when editing/creating a Blueprint, eg https://goempyrean.app.spacelift.io/blueprint/er-01K0CFKKM3V7AMV5XDXYJ71436. There is a flash of content and then an error display:

    I see now that the first half of my code snippet didn’t get copy/pasted which probably made things more difficult, I apologize. Here is the error message and stack trace from the dev console:

    And the full code block, in /src/components/CodeEditor/Monaco/utils.ts:

    const getPlatformString = (): string => {
  if (
    "userAgentData" in navigator &&
    "platform" in navigator.userAgentData &&
    navigator.userAgentData?.platform
  ) {
    return String(navigator.userAgentData.platform);
  } else if (navigator.platform) {
    // Fallback to the deprecated navigator.platform property.
    return navigator.platform;
  }
  return "";
};

  • Marcin Białoń

    Team•

    Jul 17, 2025

    Hey@Chris Mellon, we are trying to reproduce this issue without success. Could you please share a bit more about your setup? OS version. Firefox version. Maybe a screenshot of the problem.

  • Black Breeze

    •

    Jun 4, 2025

    Thanks for flagging the problem, I asked the dev team to look into it.