This is not very user friendly: you need to pick an entry as if you wanted to use it as a find query, then right-click on the find field and then click on "Delete" tooltip. It would be much more useful, if:Modal Search Window
* Added right click context menu to find/replace fields so you can now delete an entry.
* you could do RMC on a drop-down entries list and delete one
* you could delete drop-down entries items with a keyboard (just like it is possible with e.g. history entries in Firefox: the key shortcut in question is ctrl+shift+del)