When loading a dialog, first close it, then remove the whole branch,

then load, and finally open the dialog again if it was open at the
beginning. That way it's easy to edit and to update a Nasal-loaded
XML dialog.

Nasal/gui.nas

@@ -172,6 +172,11 @@ Dialog = {
     },
     # doesn't need to be called explicitly, but can be used to force a reload
     load : func {
+        var state = me.state;
+        if (state) {
+            me.close();
+        }
+        me.prop.removeChildren();
         fgcommand("loadxml", props.Node.new({"filename": me.path,
                 "targetnode": me.prop.getPath()}));
         var n = me.prop.getNode("name");
@@ -181,6 +186,9 @@ Dialog = {
         me.name = n.getValue();
         me.prop.getNode("dialog-name", 1).setValue(me.name);
         fgcommand("dialog-new", me.prop);
+        if (state) {
+            me.open();
+        }
     },
     # allows access to dialog-embedded Nasal variables/functions
     namespace : func {