diff -r 7e9dad2783bc -r f50f620771ee QTfrontend/gameuiconfig.cpp
--- a/QTfrontend/gameuiconfig.cpp	Sun Jun 19 18:45:10 2011 +0200
+++ b/QTfrontend/gameuiconfig.cpp	Sun Jun 19 20:55:34 2011 -0400
@@ -22,6 +22,7 @@
 #include <QDesktopWidget>
 #include <QInputDialog>
 #include <QCryptographicHash>
+#include <QFocusEvent>
 
 #include "gameuiconfig.h"
 #include "hwform.h"
@@ -75,6 +76,8 @@
 
     Form->ui.pageOptions->editNetNick->setText(netNick);
     
+    Form->ui.pageOptions->editNetPassword->installEventFilter(this);
+    
     int passLength = value("net/passwordlength", 0).toInt();
     setNetPasswordLength(passLength);
 
@@ -327,6 +330,24 @@
     return (netPasswordLength() == 0 || Form->ui.pageOptions->editNetPassword->text() != QString(netPasswordLength(), '\0'));
 }
 
+// When hedgewars launches, the password field is set with null characters. If the user tries to edit the field and there are such characters, then clear the field
+bool GameUIConfig::eventFilter(QObject *object, QEvent *event)
+{
+    if (event->type() == QEvent::FocusIn)
+    {
+        if ((QLineEdit *)object == Form->ui.pageOptions->editNetPassword)
+        {
+            if (!netPasswordIsValid())
+            {
+                Form->ui.pageOptions->editNetPassword->clear();
+            }
+        }
+    }
+    
+    // Don't filter anything
+    return false;
+}
+
 void GameUIConfig::setNetPasswordLength(int passwordLength)
 {
     if (passwordLength > 0)