Hi OlegBou, could you check for it among the available toolbar buttons on the Customize panel. This article will get you there:

Customize Firefox controls, buttons and toolbars

Not only is the refresh icon missing from my toolbar, but it has disappeared from the list of icons in the customize menu. Now what?

Hi mcassady, if you can't find the icon in an unexpected location, such as the "Overflow" list that drops from the >> button or on a different toolbar, then use the "Restore Defaults" buton at the bottom of the Customize windows to reset the toolbars back to their original layout and then recustomize to your liking.

Note that you may have accidentally removed button(s) from the Navigation Toolbar.

If you right-click a toolbar item in normal (non-customize) mode then you can remove this item from the toolbar.

• "Remove from Toolbar" will remove this item from the Navigation Toolbar and moves it to the Customize palette ("3-bar" Firefox menu button -> Customize)
• "Move to Menu" will move this item to the "3-bar" Firefox menu button drop-down list
• "Move to Toolbar" in the "3-bar" Firefox menu button drop-down list will move this item to the toolbar

Thanks for your prompt reply. I followed your suggestion regarding "Restore Defaults". The result shows that the refresh icon remains missing.

I did not remove the refresh icon from the navigation tool bar, either on purpose or accidentally. It is not in the drop-down list or customize menu. It has vanished.

Did you look elsewhere on the Navigation Toolbar for the combined reload/stop icon that shows as a circular arrow? This reload icon would normally appear at the left end of the Navigation Toolbar next to the back and forward buttons.

You can try to reset this pref on the about:config page via the right-click context menu to the default value.

• browser.uiCustomization.state

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Can you attach a screenshot to show how the Navigation Toolbar currently looks like?

• https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem
• use a compressed image type like PNG or JPG to save the screenshot

The problem has been solved, but the mystery remains. Suddenly the refresh icon reappeared without me having done anything. Could this have resulted from Firefox working on its system? Many thanks to both of you for taking time to respond.