Lost main menu in Konqueror. Same with Dolphin & a news reader.

[aria]

Recently, I lost the main menu tool bar (File, Edit, view, etc.) in Konqueror. Just went in it's configuration (settings) to clean the history, and the main menu in the main application disappeared.
I also lost the same main menu bar in another K-integrated application earlier (a news reader I don't remember the name, did removed it). Tried to reinstall the application, but main menu didn't reappear.
On another computer, after a fresh Kubuntu install, main menu bar never appeared in Dolphin.

What can I do and how to correct these bugs?

Thanks,

[TWPonKubuntu]

Did you try F11? That should toggle full screen mode on/off

[aria]

Did now, all the same.

It is a setting that permanently changed, and I don't know how to bring it back. It's something usually accessed through the main menu bar: View/Toolbars. But now, without the main menu bar, I cannot change it back. I cannot reactivate this bar. In the Konqueror's Toolbar Settings/Configure Toolbars, the Main Toolbar shows only buttons (Back, Forward, Home, etc.) and there's no option to add the text menu (File, Edit, View, etc.). There's also no option to add another Toolbar (did unlock the Toolbar Position and two other options appeared, but not what I needed).

The main menu bar disappeared only for one K-integrated application at a time (it is still there for other K-integrated applications).

[TWPonKubuntu]

In Dolphin,
select <Configure Toolbars>,
add "Show Menubar" to the current actions (right side panel). When you save the new configuration, the toolbar will have the <Show Menubar> button, which turns on/off the top menu: "File Edit View Go Tools Settings Help"

I don't use Konqueror, but it may have a similar option.

[claydoh]

To toggle the menu bar in most KDE applications, ctrl-m should do it (the file, edit, etc )
By default, this menu is off in Dolphin.

[aria]

Thank you very much, both worked!