MP campaign additions/fixes:

- Store tab & cargo spawning
- Sub & shuttle lists and level seed box are disabled when a campaign is active.
- Campaign UI is recreated if a new campaign is started while another one is active.

Barotrauma/BarotraumaClient/Source/GUI/GUIScrollBar.cs

@@ -36,7 +36,11 @@ namespace Barotrauma
         public bool Enabled
         {
             get { return enabled; }
-            set { enabled = value; }
+            set
+            {
+                enabled = value;
+                bar.Enabled = value;
+            }
         }
 
         public float BarScroll
@@ -161,6 +165,8 @@ namespace Barotrauma
 
             base.Update(deltaTime);
 
+            if (!enabled) return;
+
             if (MouseOn == frame)
             {
                 if (PlayerInput.LeftButtonClicked())