Merge remote-tracking branch 'origin/develop' into develop-preview

# Conflicts:
#	Packages/src/CHANGELOG.md
#	Packages/src/package.json

Packages/src/Icons.meta

@@ -1,8 +0,0 @@
-fileFormatVersion: 2
-guid: 7a55e246f37df405bac88eac692e3a86
-folderAsset: yes
-DefaultImporter:
-  externalObjects: {}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Packages/src/Runtime/UIParticleProjectSettings.cs

@@ -5,7 +5,6 @@ using UnityEngine;
 
 namespace Coffee.UIExtensions
 {
-    [Icon("Packages/com.coffee.ui-particle/Icons/UIParticleIcon.png")]
     public class UIParticleProjectSettings : PreloadedProjectSettings<UIParticleProjectSettings>
     {
         [Header("Setting")]

Packages/src/Runtime/UIParticleProjectSettings.cs.meta

@@ -5,7 +5,7 @@ MonoImporter:
   serializedVersion: 2
   defaultReferences: []
   executionOrder: 0
-  icon: {instanceID: 0}
+  icon: {fileID: 2800000, guid: 5f0675613942149309588d556e33d990, type: 3}
   userData: 
   assetBundleName: 
   assetBundleVariant: 

Packages/src/Runtime/Utilities/ParticleSystemExtensions.cs

@@ -187,6 +187,8 @@ namespace Coffee.UIParticleInternal
 
         public static bool IsSubEmitterOf(this ParticleSystem self, ParticleSystem parent)
         {
+            if (!self || !parent) return false;
+
             var subEmitters = parent.subEmitters;
             var count = subEmitters.subEmittersCount;
             for (var i = 0; i < count; i++)