expose event not received by Open GL window in X11 application upon moving app window

Wendel Dean Renner WendelDRenner@comcast.net
Mon Nov 4 17:35:00 GMT 2013

I have compiled and linked an existing X/Motif/Open GL program
under cygwin.  So far the only problem I have seen is what happens
when I move the main application window.

I have an array of drawing widgets in the main application window.
Where the drawing widget is strictly an X window, if I move the main
application window, the contents
continue to be visible without an expose event occuring (and so the
draw loop is not called).

But in the Open GL drawing area window (using glx) the contents disappears
and one sees only the back ground color.   There is no expose event
generated.  If I click the mouse on the window, an expose even is generated
and it redraws.  The same happens if I change the size of the window,  but
covering and uncovering the window with say a cygwin term window
does not generate an expose event.  Covering with a child of the application
and uncovering does generate an expose event.

The x window is created with the line
  %RUN% XWin -multiwindow -clipboard -silent-dup-error -wgl

where I added the -wgl flag.
Doing export LIBGL_ALWAYS_INDIRECT=1 before I run the application
does not make any difference.
I used a startxwin.bat script and modified it to run my application instead
of a xterm. That allowed for an icon on the desktop to run the bat program
to run the application.

I also noted, like with Exceed, I cannot get a visual in the overlay planes,
which I can do under Linux.  I do not have glxinfo and can't figure out
what package has that.

cygwin was downloaded an installed on a Windows 7 computer just
last week.   The graphics card is an nvidia quadro fx 3800, driver
version 320.92
On Performace Options:
Show window contents while dragging is unchecked.

The program runs under Linux (was developedorginally under SGI IRIX) and
I have been using Exceed,Exceed 3D, and Exceed XDK from OpenText 
(formally Hummingbird) to run on a Windows platform.

I have only recented noted that OSF/Motif is now available with cygwin
as opposed to the prior LessTiff implementation of motif, as of Oct 2012
My X/Motif program would not run correctly with LessTiff because
of behavior differences where I was doing a lot of  drawing widgets 
to the same place and managing and unmanaging them so that only one would
appear at a time, allowing the user to change the layout of the draw area

Thanks to any advice available.

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