Please provide a public link (no password) that we can check out. No Personal Information Please !

I see you are using a beta version. Have you tried the normal FF?

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Opening in Safe mode did not solve the problem but I have discovered that a program called Video Downloader Ultimate which was running with FF appears to be causing the problem. I switched it off and problem sorted. It appears as a blue arrow on a white background at the top right hand of the FF screen. Funny it only appeared to effect the Aer Lingus Site.

Hello Brayman,

'Video Downloader Ultimate' is not an extension from the official addons.mozilla.org page - hence Safe Mode didn't solve the problem, as it disables add-ons from that page only.

Unless you installed that extension yourself - would you please remove it  ?

These search results will explain why I ask .....

That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

McCoy said

Unless you installed that extension yourself - would you please remove it  ?

After you have done so, You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Thank you very much for your prompt reply. It sent me in the right direction. Cheers