message: Columns: Added internal tracking of a few flag temporarily, to facilitate the work of third-parties who have columns patches.
diff: @@ -423,6 +423,8 @@ struct ImGuiColumnsSet
  {
  ImGuiID ID;
  ImGuiColumnsFlags Flags;
  + bool IsFirstFrame;
  + bool IsBeingResized;
  int Current;
  int Count;
  float MinX, MaxX;
  @@ -436,6 +438,8 @@ struct ImGuiColumnsSet
  {
  ID = 0;
  Flags = 0;
  + IsFirstFrame = false;
  + IsBeingResized = false;
  Current = 0;
  Count = 1;
  MinX = MaxX = 0.0f;
  