[vdr] cSkinSTTNGDisplayMenu::SetButtons overwrites the message set via SetMessage

[Klaus Schmidinger]

Luca Olivetti wrote:
> As the subject says. ST:TNG is the only skin where this happens, since 
> it shares the same line for both things. And you can see the "remains" 
> of the message in the space between each button.
> Maybe I'm wrong, but I shouldn't be forced to stop calling SetButtons if 
> there's a message active (at least if I repeatedly[*] call SetButtons 
> after calling SetMessage it works fine with every other skin).
> 
> [*] I change the help at each screen refresh based on the menu 
> selection, while I only need to show a message from time to time.

Well, I can check 'message' in cSkinSTTNGDisplayMenu::SetButtons(),
and not set the buttons if it is true, but that will result in the
buttons having their _old_ values after the message disappears.

Generally the buttons are not supposed to be changed while a message
is being displayed. Ok, I haven't written that anywhere explicitly,
but that's how it's meant, so I can add that remark if you like.

Klaus