choosing a player name with a space only partially prevented

[SimonHeimberg]

Describe the bug
In the dialogue to join a multiplayer game (LAN / direct ip), the button to join is disabled when the human chooses a name with a space in it. But with a double click on the game or click and enter, joining continues anyway.

To reproduce
Steps to reproduce the behavior:

1. Start widelands

2. Type "p" for a multiplayer game "LAN / direct IP"

3. Enter a valid player name here (like "testHost")

4. Click the button to "Host a new game"

5. Click the button to Choose a map

6. Choose any map

7. Confirm with double-click or ok button

8. Start a 2nd instance of widelands
   (from a terminal/"new window" in context menu in gnome/on another computer in the lan/...)

9. Type "p" for a multiplayer game "LAN / direct IP"

10. Enter a name for your player containing a space (like "join 2 win")

11. The buttons to "Host new a game" and "Join a game" are disabled
    (This is expected. The frame of the player name is in red and the reason is written in its tooltip)

12. Double-click on the game listed in the list => you join with the illegal name

13. click the button back

14. click on the game in the list and type enter => you join with the illegal name

Expected behavior
Choosing a player name containing a space (like "me too") is not possible in any way. (Or possible in all ways if it does not matter.)

Version:

• OS: Debian 6.1.27, flatpak
• Widelands Version: v1.1

Additional info:
Was first mentioned in the forum in https://www.widelands.org/forum/topic/5797/?page=1#post-40394 somewhere below the title add possibility to detect human players in multiplayer game