Hi Cheryl Cope, Did @cor-el's response from 4 months ago (1265543) resolve this or is this an ongoing issue since then?

Try with clearing cookies and cache.

To remove Cookies; Select Privacy & security. Then scroll down to "cookies and site data". Then press the button on the right side called manage data. Use the search bar to look for the site. (There may be more than one entry. Remove All of them)

To Clear the Cache; Press the button on the right side called Clear data.Then tick cached web content and then press clear button.

Note that some websites change to mobile view if you make the window quite small or zoom the page (zooming affects the reported dimensions).

Does this only happen on specific websites ?

You can remove all data stored in Firefox for a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox for this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data for that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data for that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox