Hi Oliver,
While glancing through one of your recent commits, I noticed this statetement.
+<para>You may notice that the About dialog is modal - that is, the Product View window cannot be
+          accessed while the About window is open. This is a consequence of using
+            <computeroutput>SHOWTOP</computeroutput> as the parameter for <emphasis role="italic"
+            >dlg~execute()</emphasis> in the <computeroutput>ProductView</computeroutput>'s
+            <emphasis role="italic">about</emphasis> method.
That the dialog is modal is a consequence of using the execute() method.  It is not a consequence of the value of the show argument.
I.e., if the show argument were "HIDE" the dialog would still be  modal. 
In general, the execute() and executeAsync() methods create modal dialogs and the popup() and popupAsChild() methods create modeless dialogs. 
Mark Miesfeld