Many thanks, Mark.
Well, I don't think I can wait till 3011 for a better implementation, so I guess I'll make do with non-constant margins and continue to try to get my head around the current implementation.

From: Mark Miesfeld []
Sent: 17 August 2011 14:15
To: Open Object Rexx Users
Subject: Re: [Oorexx-users] ooDialog - dlgAreaU and margins

On Tue, Aug 16, 2011 at 4:36 PM, Oliver Sims <> wrote:
I'm just getting to grips (I hope) with re-sizable dialogs, and have been playing about with dlgAreaUDemoThree.rex (from the ooDialog Samples folder). I notice that when I size the dialog, the dialog margins also change. Is there any way to prevent this? That is, can the margins be kept the same size regardless of the size of the dialog (assuming that, like dlgAreaUDemo you set a minimum size for the dialog)?
Not in the current implementation.  You could probably enhance the DlgAreaU class to do it.
Jon Wolfers wrote the class originally and it is a clever implementation.  However, it is has several restrictions and at some point I would like to write a class, probably a mixin class, that removes the restrictions.
DlgAreaU parses the source code to determine the dialog controls and their original dimensions.  Because of this, it will only work for UserDialog dialogs that are not tokenized.
I would implement the functionality in native C++ code, which would probably give better performance.  The Rexx side, the class, would mostly consist of methods that allow the programmer to specify how the resizing is done.  Things like minimum and maxim size would be set by the programmer and enforced by the native code. 
I would probably have a way to 'pin' a control, which I think is what you mean by the margins.  I.e., if you had a list-view in the upper left corner you could 'pin' the top of the list-view to the top edge of the dialog and pin the left edge of the list-view to the left edge of the dialog.  This would have the effect of keeping the top-left corner of the list-view at the same point in the dialog and all the shrinking and expanding would take place on the bottom and right.
For myself, not being able to use a ResDialog is a serious disadvantage, but it is likely to be some time before I get to creating an enhancement.  It is one of the first things I'd like to do as soon as I get 4.2.0 released.  Which may not be until the third millennium at my current rate.  <grin>
Mark Miesfeld