Thank you for the input but this is not the reason. The combo ‘alt-f’ is not doing anything, I have the FindKeyConflicts plug-in installed and that does not identify a conflict. The closest a review of All Key Mappings comes to is [alt+f10], [alt+f2], [alt+f3], [alt+f5].
I genuinely think this is due to a plug-in rewriting the menu. The ‘F’ is no longer underlined in ‘File’ on the menu bar whereas all the other hot-keys appear as they should. Testing a theory that this shortcut was due to a key mapping conflict, I tested by remapping a shortcut to ‘alt+e’. The test worked in that it executed the short-cut instead of activating the Edit panel of the menu. There is no change in appearance of the Edit menu item when it a key conflict.
Still wondering
[quote=“FichteFoll”]Some package most likely added a key binding to “alt+f”, which now prevents you from focusing menu items with it.
Check with packagecontrol.io/packages/Edit%20Preferences[/quote]