TabPage with HTML Text

You can create a custom TabPageHtml class like this:

public class TabPageHtmlText : TabPage
{
  protected override void OnWebRender(dynamic config)
  {
    base.OnWebRender((object)config);

    // escape the html text.
   config.caption = TextUtils.EscapeText(this.Text, true /* allowHtml */, this.UseMnemonic, false);
   }
}

All it needs is to escape the html text differently to allow for html tags.

Be careful with the html since the tab buttons may not be able to fully adjust their size. See small test below using <b>tabPage</b><big><big><big>4</big></big></big></big>.