Subresources cannot be read by means of get-values.

Callbacks *must* return; e.g. a (reset) from within a callback is
not allowed.  This is a bug in Xt.

Xt doesn't notice when ports that have been registered as input source
with context-add-input are closed.  In this case, the select() fails.

error.c:  Warning msg handler is now part of application context

Missing:

  keycode translators
  case converters
  shared graphics contexts
  selections

  2.
  XtScreen
  XtDisplayOfObject
  XtScreenOfObject
  XtWindowOfObject

  7.
  XtAddGrab
  XtRemoveGrab
  XtGrabKey
  XtUngrabKey
  XtGrabKeyboard
  XtUngrabKeyboard
  XtGrabButton
  XtUngrabButton
  XtGrabPointer
  XtUngrabPointer
  XtSetKeyboardFocus
  XtCallAcceptFocus
  XtAppPending
  XtAppPeekEvent, XtAppNextEvent, XtAppProcessEvent, XtDispatchEvent (?)
  Xt{Add,Remove,Insert}EventHandler (?)
  Xt{Add,Remove,Insert}RawEventHandler (?)
  XtBuildEventMask (?)

  9.
  XtGetSubresources (?)
  XtGetApplicationResources
  XtGetSubvalues, XtSetSubvalues (?)

  10.
  XtAppAddActionHook (?)
  XtRemoveActionHook (?)

  11.
  XtAppSetSelectionTimeout
  XtAppGetSelectionTimeout
  XtSetWMColormapWindows