hello, it is not possible to reliably remove that option (it would be possible to circumvent that with a keyboard shortcut or through launching firefox in safe mode).

You can also open the history in the sidebar and clear history that way. There is also "Forget About This Site" available in the right-click context menu.

If you want a record of visited websites then you should use means at the OS level that can't be bypassed.

• https://support.mozilla.org/kb/Parental+controls