Android Question WobbleMenu Source Error

[HassanProgrammer]

Hello
I downloaded the source for b4a from the link below:

[B4X][XUI] WobbleMenu - a cross platform animated bottom navigation

Hi everyone, This is a B4X compatible bottom navigation. It has 4 types of tab changing animation and 3 types of icon revealing animation. WobbleMenu Author: @Biswajit Version: 1.5 Dependency: JavaObject, BitmapCreator, XUI WobbleMenu Functions: GetCurrentTab As Int Get the current tab id...

www.b4x.com

Source compilation is done correctly but this error occurs when running the application:

wobblemenu_designercreateview (java line: 519)
java.lang.NumberFormatException: For input string: "null"
    at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1306)
    at java.lang.Double.parseDouble(Double.java:547)
    at anywheresoftware.b4a.BA.ObjectToNumber(BA.java:684)
    at b4a.example.wobblemenu._designercreateview(wobblemenu.java:519)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:213)
    at anywheresoftware.b4a.objects.CustomViewWrapper.AfterDesignerScript(CustomViewWrapper.java:67)
    at anywheresoftware.b4a.keywords.LayoutBuilder.loadLayout(LayoutBuilder.java:162)
    at anywheresoftware.b4a.objects.ActivityWrapper.LoadLayout(ActivityWrapper.java:209)
    at b4a.example.main._activity_create(main.java:349)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:213)
    at b4a.example.main.afterFirstLayout(main.java:105)
    at b4a.example.main.access$000(main.java:17)
    at b4a.example.main$WaitForLayout.run(main.java:83)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6121)
    at java.lang.reflect.Method.invoke(Native Method)

Please help me to fix this error