public sealed class CoreModule : ArcGIS.Desktop.Framework.Contracts.Module, System.ComponentModel.INotifyPropertyChanged  

//In the module class..
public override string[] GetSuggestedCMDIDs(string activeTabID)
{
  //Return the static list of daml ids you want to be the (suggested) 
  //defaults relevant to the given tab. It can be none, some, or all of the
  //commands associated with the activeTabID.
  //In this example, there are two tabs. This example arbitrarily
  //identifies just one command on each tab to be a default to show in the
  //command search list (when _that_ particular tab is active)
  switch (activeTabID)
  {
    case "CommandSearch_Example_Tab1":
      return new string[] { "CommandSearch_Example_Button2" };
    case "CommandSearch_Example_Tab2":
      return new string[] { "CommandSearch_Example_Button4" };
  }
  return new string[] { "" };
}