It won't let me edit my post, so to add more detail, I can only close the download dialog box by pressing ESC, the Cancel button does not respond. The only thing on the entire dialog box that seems to respond is the format drop-down.

The problem is apparently intermittent, randomly it will work, but it freezes FAR more than it works.

Thank you.

You can find "Edit this question" under the "Question Tools" menu in the sidebar. For a reply, "Edit this post" is in the three-dot menu next to a reply.

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

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

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