Update cached scroll offset for inactive tabs when updating chat text…

…. Fixes bug where inactive tabs wouldn't scroll to the bottom on new chat.

EndlessClient/HUD/Chat/ChatPanelTab.cs

@@ -152,6 +152,7 @@ protected override void OnUpdateControl(GameTime gameTime)
                 }
                 else
                 {
+                    _cachedScrollOffset = Math.Max(0, _renderables.Count - 7);
                     _label.ForeColor = Color.White;
                 }
             }