Fix for NRE on entry into flight scene because Update can be called before AppLauncher is ready
Fix for NRE on entry into flight scene because Update can be called before AppLauncher is ready

--- a/KerbalEngineer/Flight/FlightAppLauncher.cs
+++ b/KerbalEngineer/Flight/FlightAppLauncher.cs
@@ -179,6 +179,9 @@
 
         protected virtual void Update()
         {
+            if (Button == null)
+                return;
+
             if (FlightEngineerCore.IsDisplayable && Button.IsEnabled == false)
             {
                 Enable();