Does the top part of the page look like the attached when you first open it?

There is something a little odd going on with the promotional lines at the top of the page. After I X off the blue banner, sometimes the page loads with a blank gray circle instead of my initials, and then after a delay, the "Upgrade Account" line opens and pushes the rest of the page down.

Do you use any add-ons that remove or hide ads or other promotional content in web pages? If so, try using their toolbar buttons to make an exception for Dropbox and see whether that makes any difference.

(P.S. I assume you do have not created a userChrome.css file that might modify Firefox's toolbar area.)

Yes, it looks like your attachment. As soon as I click on on an item it moves up under the page header.

I tried turning off the add blockers to no avail.

It was working fine yesterday, I minimized the details pane and then it just started doing this. I cleared the last four hours a history and cleared the cache at that time, no change.

Something in Firefox on this computer is out of order, it works fine the computer in my other office.

I can't replicate it when moving around among the files and folders, or minimizing details, reloading, changing folders, etc. Puzzling.

Usually the only reason for the top part of a page to be "behind" the toolbars is if a script in the page, or an add-on script, applied a negative top margin -- a positive top margin moves the content down, a negative top margin moves it up -- or removed/hid something that was necessary for a negative top margin to make sense.

Does it make any difference to zoom out (hold Ctrl, and tap - a couple times) and then reload or try a different folder? Just wondering whether there might be some issue with perceived resolution on your current display.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection. You can check the Web Console for relevant-looking messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

You can try these steps in case of issues with webpages:

You can reload webpage(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Settings).

"Remove the Cookies" for websites that cause problems:

• Settings -> Privacy & Security
  Cookies and Site Data: "Manage Data"

"Clear the Cache":

• Settings -> Privacy & Security
  Cookies and Site Data -> Clear Data -> [X] Cached Web Content -> Clear

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 userChrome.css is causing the problem.

• switch to the DEFAULT 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

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

I tried zooming in and out, no difference.

I tried the items Cor-el suggested, no difference. I even shut the computer down and restarted.

Dropbox is the only page with which I am having this issue.

Not sure what changed, it started working like it should about mid-morning. Was using it with the hidden text, came back a couple hours later and it was back to normal.