Try updating browser to latest release Ver 54 From Menu Bar : Help then About or which ever way you do so. If problem persists please come back and update. If solves your problem please come back and close this as solved.

Our department is running on the ESR update channel. The "About Mozilla Firefox" form says Firefox is up to date. I need a fix that works with the latest version of the ESR.

This issue could be theme related, either a Firefox theme or a Windows theme.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

The steps above did not help. If I do "Refresh Firefox" the 1st time I open FF the problems go away (the drop down lists are single spaced and I can successfully do Print to PDF). But, once I close and reopen FF the problems return. The problem with Print to PDF is that there is no text in PDF created. I think it may be a font issue but I don't know for sure.

We found that for some reason going into about:config and changing the value of this preference name to false fixes both issues. Any ideas? Do we need to tell all our users to go into about:config to make this change and hope they don't mess anything up?

browser.tabs.remote.autostart.2;false

zajlzoo said

We found that for some reason going into about:config and changing the value of this preference name to false fixes both issues. Any ideas? Do we need to tell all our users to go into about:config to make this change and hope they don't mess anything up?

browser.tabs.remote.autostart.2;false

Yes. Websites often specify style rules for the <option> elements of <select> controls. In Firefox 49-53, with multiprocess enabled, most of those style rules are ignored. Old thread from the Firefox 49 days: dropdown.

There is work in process to fix that, and some of the fix may have landed in Firefox 54, but users are still mentioning issues with font sizes/weights in Firefox 54. Hopefully in Firefox 55?

Try to set dom.forms.select.customstyling to false.