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(Courtesy of Donna Converse, converse@x.org; 5/14/92)

> I am building a widget needs to know if it is visible. I set the visible
> interest field in Core and if my window is completely obscured, the Core
> visible flag goes FALSE. However, if my window is iconified, the flag
> stays set to TRUE.

Right, everything is implemented correctly.  This demonstrates a "deficiency"
in the X protocol, and the Core widget is reflecting the capabilities of the
protocol.  (The "deficiency" is that the information is available in one way,
in this case an inconvenient way.)  The Xt specification is accurate, in
the second and third paragraphs of section 7.10.2, so read this section
carefully.  The visible field will not change in response to iconification.

A VisibilityNotify event will not be received when the window goes from
viewable to unviewable, that is, when the widget or an ancestor is unmapped;
that is, when iconification occurs.  This is the protocol deficiency.
Visibility state and viewable state have specific meanings in the X protocol;
see the glossary in your Xlib and X protocol reference manual.

> Is this a problem with "mwm" or is there something
> else which needs to be done?

You'll see this with any window manager, with no window manager.

> If the problem is "mwm", what is the fastest
> way to determine if a window is iconified? 

As an application writer, keep track with a global Boolean in an action
routine with translations for MapNotify and UnmapNotify on the Shell widget
which contains your custom widget.  As the custom widget writer, see the
map_state field returned by a call to XGetWindowAttributes.  These are
suggestions.