fix customizing widgets not working

Shared/views/CustomWidget/CustomWidgetModel.swift

@@ -79,21 +79,32 @@ class CustomWidgetModel: ObservableObject, Codable, NSCopying {
     @Published var isSaved: Bool
     @Published var createdDate: Date
     
+    private var oldBackground: CustomWidgetBackGroundOptions?
+    private var oldBackgroundImages: [(Image, String)]?
+    
     public var backgroundImages : [(Image, String)] {
+        if let oldBackgroundImages = oldBackgroundImages,
+           oldBackground == background  {
+            return oldBackgroundImages
+        }
+        
+        oldBackground = background
+        
         if background == .random {
             var blah = [(Image, String)]()
             for _ in 0...CustomWidgetModel.numberOfBGItems {
                 let image = CustomWidgetBackGroundOptions.selectable.randomElement()?.image ?? CustomWidgetBackGroundOptions.defaultOption.image
                 blah.append((image, UUID().uuidString))
             }
-            return blah
+            oldBackgroundImages = blah
         } else {
             var blah = [(Image, String)]()
             for _ in 0...CustomWidgetModel.numberOfBGItems {
                 blah.append((background.image, UUID().uuidString))
             }
-            return blah
+            oldBackgroundImages = blah
         }
+        return oldBackgroundImages!
     }
     
     enum CodingKeys: CodingKey {