ASP.NET WebForms - Issues disabling list item

Question

I am running (ASP.NET Web Forms) VB.Net code and in the aspx page, i have something like this:

<ul id="tabsdefault" class="tab-menu">
        <li id="accessingIndividuals" runat="server"><a>Accessing Individuals</a></li>
</ul>

and in the code behind file, i have this code:

accessingIndividuals.Disabled = true

However, before upgrading to .NET 4.6, this code worked and now after the upgrade, it does not disable the list item.

I have also manually changed the aspx page item with this:

<ul id="tabsdefault" class="tab-menu">
        <li id="accessingIndividuals" runat="server" disabled="disabled"><a>Accessing Individuals</a></li>
</ul>

but that did not work and nor did the following:

<ul id="tabsdefault" class="tab-menu">
        <li id="accessingIndividuals" runat="server" disabled="true"><a>Accessing Individuals</a></li>
</ul>

Any idea what has changed in .NET Framework or how can disable this item?

Looking at the page source using Developer Tools, the output is like this:

    <ul id="tabsdefault" class="tab-menu">
        <li id="accessingIndividuals" enabled="false" disabled="disabled" class="selected"><a>Accessing Individuals</a></li>
</ul>

Answer 1

Looks like all new Browsers ignore the disable attribute on a list item. One possible solution is:

    li[disabled]
    {
      pointer-events: none;
      opacity: 0.6;
    }