Please provide a screenshot of that issue.

https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem

It is best to use a compressed image type like PNG or JPG to save the screenshot and make sure that you do not exceed a maximum file size of 1 MB.

Then use the Browse .... button below the Post a Reply text box to upload the screenshot.

Here is a screenshot of the issue

Start Firefox in Safe Mode {web link} See if you still have the problem.

Do you use Trend Micro antivirus software or toolbar? If you do so, please try to update your Trend Micro software or disable Trend Micro add-ons in Firefox.

If Safe Mode does not help immediately, before returning to normal mode please try this:

Firefox 30 switched most plugins from "Always Activate" to "Ask to Activate" so that sites need to ask your permission to run them. Some plugins that interact with the user interface are glitchy in this mode.

To test whether that is the issue, try switching your plugins to one of the other options:

• Always Activate - all sites can use the plugin without specific permission
• Never Activate - no sites can use the plugin (unless you give them permission through the Permissions page of the Page Info dialog while viewing the site)

To make this change open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Plugins. You can change the "Ask to Activate" ones to one of the other options and see whether that helps.,

Create a new window (Ctrl+n or Ctrl+Shift+p) to test. Any difference?