Hm, I should have posted the actual steps I did to reproduce this then.
1. Run ./widelands --double
2. In window A, go to multiplayer game and host a new local (LAN) game.
3. In window B, go to multiplayer game, and join the game (enter "localhost" in the textbox for server name).
4. Let one of the windows be a spectator and try to click on the legitimate player's buildings.
>I cannot do network plays now :-(
Hm, I should have posted the actual steps I did to reproduce this then.
1. Run ./widelands --double
2. In window A, go to multiplayer game and host a new local (LAN) game.
3. In window B, go to multiplayer game, and join the game (enter "localhost" in the textbox for server name).
4. Let one of the windows be a spectator and try to click on the legitimate player's buildings.