anchor.diff:                  if Keys.Control = Control.ModifierKeys && Keys.C = key then handleFormCopy form (EventArgs ())
                   if Keys.Control = Control.ModifierKeys && Keys.V = key then handleFormPaste false form (EventArgs ())
                   if Keys.Delete = key then handleFormDeleteEntity form (EventArgs ())
  +                if Keys.Escape = key then deselectEntity form world
   
       let private handleFormClosing (_ : GaiaForm) (args : CancelEventArgs) =
           match MessageBox.Show ("Are you sure you want to close Gaia?", "Close Gaia?", MessageBoxButtons.OKCancel) with
  
positive.code:             if nCode >= 0 && (wParam = IntPtr WM_KEYDOWN || wParam = IntPtr WM_SYSKEYDOWN) then
                  let key = lParam |> Marshal.ReadInt32 |> enum<Keys> 
                  match form.GetFocusedControl () with
                  | :? TextBox -> handleKeyboardInput key true form
                  | :? SymbolicTextBox -> handleKeyboardInput key true form
                  | _ -> handleKeyboardInput key false form
              GaiaForm.CallNextHookEx (form.HookID, nCode, wParam, lParam)) |> ignore
          tryRun3 runWhile sdlDeps (form : GaiaForm)
  
  
negative.code:         not form.editWhileInteractiveCheckBox.Checked
  
      let private tryMousePick (form : GaiaForm) mousePosition world =
          match form.entityPropertyGrid.SelectedObject with
          | :? EntityTypeDescriptorSource as entityTds ->
              let entity = entityTds.DescribedEntity
              if Math.isPointInBounds mousePosition (entity.GetBounds world)
              then (Some entity, world)
              else
                  let (entities, world) = getPickableEntities world
                  let pickedOpt = World.tryPickEntity mousePosition entities world
                  match pickedOpt with
                  | Some entity ->
                      selectEntity form entity world
                      (Some entity, world)
                  | None -> (None, world)
          | _ -> (None, world)
  
      let private handleNuChangeParentNodeOpt form _ world =
          refreshHierarchyTreeView form world
  