[Tutorial] How to increase size of 1Password pop-up in Firefox

People have been complaining about entry titles being cut off for so many years now, and there is still no official fix in sight. But I have found a workaround that increases the pop-up size to the maximum allowed on Firefox, and I want to share that for anyone interested.

Mind you, this makes use of a hidden legacy setting, which might get removed soon, so it’s not a long-term solution. The devs should finally make the pop-up resizable since it would only take an hour of their time (or an AI agent that runs in the background while they work on the more important features 🙂). I would also be willing to contribute to the extension, but as far as I know, it is closed source.

I have only tested this on Linux, but it should work on Windows and macOS too.

• Open about:config by typing it into the address bar

• Set toolkit.legacyUserProfileCustomizations.stylesheets to true

• Right click into the 1Password pop-up and select View Page Source

• Copy the 1Password UUID from the address bar. It looks like this: 767400c8-d3b3-4fa0-a721-a3ca596818f3. And it is different for each browser profile.

• Open about:profiles by typing it into the address bar

• Open the root directory of the profile that is currently in use

• Create a folder named chrome. Inside that folder create a file named userContent.css with the following content:

• @-moz-document url-prefix("moz-extension://INSERT_UUID_HERE/popup/") {
      /* resize 1Password popup */
      body {
          width: 800px !important;
          height: 600px !important;
      }
  
      #mainUI {
          grid-template-columns: 350px calc(100vw - 350px) !important;
      }
  
      /* remove word break to use all available space */
      #itemListPane span[class*="sprinkles_wordBreak_break-word"] {
          word-break: break-all !important;
      }
  }

  Insert your UUID at the marked spot in the code and save the file

• Restart Firefox

Result