Backport fix for window being repositioned after hiding, then reshowing

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@45691 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/toplevel.cpp

@@ -828,13 +828,17 @@ bool wxTopLevelWindowGTK::Show( bool show )
         GtkOnSize();
     }
 
-    // This seems no longer to be needed and the call
-    // itself is deprecated.
-    //
-    //if (show)
-    //    gtk_widget_set_uposition( m_widget, m_x, m_y );
+    wxTopLevelWindowBase::Show(show);
 
-    return wxWindow::Show( show );
+    if (!show)
+    {
+        // make sure window has a non-default position, so when it is shown
+        // again, it won't be repositioned by WM as if it were a new window
+        // Note that this must be done _after_ the window is hidden.
+        gtk_window_move((GtkWindow*)m_widget, m_x, m_y);
+    }
+
+    return true;
 }
 
 void wxTopLevelWindowGTK::Raise()