Custom Tag Helper cannot be found in theme

I have created a custom Tag Helper and now I would like to use that in my theme but the .cshtml cannot find it. The application sucessfully compiles and runs but I do not see my tag helper. The intellisense indicates that it cannot be found. But I cant see why. Can someone please help me. What do I need to do to create a custom TagHelper in my plugin and use it in my theme?

In my plugin I have created

namespace Nop.Web.Framework.TagHelpers.Shared
{
    [HtmlTargetElement("custom-date-picker",
        Attributes = DayNameAttributeName + "," + MonthNameAttributeName + "," + YearNameAttributeName,
        TagStructure = TagStructure.WithoutEndTag)]
    public class CustomDatePickerTagHelper : TagHelper
    {
        .......other code.......
    }

In my theme I have added

<custom-date-picker 
                                ....other attr
                                />

In the viewImports there a reference to Nop.Web.Framework

@addTagHelper *, Nop.Web.Framework
...other stuff...
@using Nop.Web.Framework
@using Nop.Web.Framework.Extensions
@using Nop.Web.Framework.Infrastructure
@using Nop.Web.Framework.Models
@using Nop.Web.Framework.Security.Captcha
@using Nop.Web.Framework.Security.Honeypot
@using Nop.Web.Framework.Themes
...other stuff...

Did you solve this issue?
I did custom tag helpers for nop 4.20 but my solution doesn't work for nop 4.30.