To reproduce:
- have the Remote Config package installed
- Open the Remote Config Management window
- Add a new Rule
- Push
- notice the window will stay in Loading Please Wait for a very long time
- if you close nad open the RC Manager window agian it refreshes and works normally

Sometimes, an error will appear int he console, but not allways:
KeyNotFoundException: The given key was not present in the dictionary.
System.Collections.Generic.Dictionary`2[TKey,TValue].get_Item (TKey key) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
Unity.RemoteConfig.Editor.RemoteConfigDataManager.GetRuleByID (System.String ruleId) (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/RemoteConfigDataManager.cs:304)
Unity.RemoteConfig.Editor.RemoteConfigWindowController.OnPostAddRuleFinished (Unity.RemoteConfig.Editor.RuleResponse ruleResponse, System.String oldRuleID) (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/RemoteConfigWindowController.cs:368)
Unity.RemoteConfig.Editor.WebUtility.ParseAddRuleResponse (System.String json, System.String oldRuleId) (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/WebUtility.cs:493)
Unity.RemoteConfig.Editor.WebUtility+<_PostAddRule>d__44.MoveNext () (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/WebUtility.cs:322)
Unity.RemoteConfig.Editor.WebUtility.UpdateCoroutine () (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/WebUtility.cs:694)
Unity.RemoteConfig.Editor.WebUtility.Update () (at Library/PackageCache/com.unity.remote-config@1.0.0-preview/Editor/WebUtility.cs:678)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
System.Delegate.DynamicInvokeImpl (System.Object[] args) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
System.Delegate.DynamicInvoke (System.Object[] args) (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
UnityEditor.EditorApplication.Internal_CallUpdateFunctions () (at <ed82b0b80ec5457da3c2e9cdf90adc95>:0)