Make sure that toolbars like the "Navigation Toolbar" and the "Bookmarks Toolbar" are visible.

• Firefox menu button > Options
• View > Toolbars (press F10 to display the hidden Menu bar)
• Right-click empty toolbar area

Use Toolbar Layout (Customize) to open the Customize window and set which toolbar items to display.

• check that "Bookmarks Toolbar items" is on the Bookmarks Toolbar
• if "Bookmarks Toolbar items" is not on the Bookmarks Toolbar then drag it back from the toolbar palette into the Customize window to the Bookmarks Toolbar

• if missing items are in the toolbar palette then drag them back from the Customize window on the toolbar
• if you do not see an item on a toolbar and in the toolbar palette then click the "Restore Default Set" button to restore the default toolbar setup

• https://support.mozilla.org/kb/How+to+customize+the+toolbar
• https://support.mozilla.org/kb/Back+and+forward+or+other+toolbar+items+are+missing

Thank you very much, this has definitely solved my problem !

I should like to indicate one thing though, which you might want to reword in your instructions:

NONE among my items were in the standard toolbar palette because they were all "custom icons", i.e., Banks, Suppliers' Websites, etc...; this means that the only way to restore them was to click on "customize", then "restore default set" Cheers - Carl

You're welcome

The items that you mentioned are bookmarks and those items are part of the "Bookmarks Toolbar items" element that keeps the bookmarks and that is positioned by default on the Bookmarks Toolbar.