Register a script oninit in /editcontent.aspx to allow for tab switching.

umbracoPage.Init

public class MyApplication : Umbraco.Web.UmbracoApplication
{
  protected override void OnApplicationStarted(object sender, EventArgs e)
  {
    umbracoPage.Init += (p, args) =>
    {
      var page = p as umbracoPage;
      if (page == null)
          return;
      var request = page.Page.Request;
      var path = request.Path.ToLower();
      if (!path.EndsWith("/editcontent.aspx"))
          return;
  
      var tab = request.QueryString["tab"];
      if(!string.IsNullOrEmpty(tab))
      {                                
        var setActiveTab = "setActiveTab('body_TabView1','body_TabView1_tab0" + tab + "',body_TabView1_tabs);";
        page.Page.ClientScript.RegisterClientScriptBlock(GetType(), "OpenTab", "<script> $(function () { " + setActiveTab + " })</script>");
      }
    };
  }
}