diff --git a/Nasal/gui.nas b/Nasal/gui.nas
index 9084dcfc4..637e32515 100644
--- a/Nasal/gui.nas
+++ b/Nasal/gui.nas
@@ -422,7 +422,7 @@ showWeightDialog = func {
         cap = t.getNode("capacity-gal_us", 1).getValue();
 
         # Hack, to ignore the "ghost" tanks created by the C++ code.
-        if(cap < 1) { continue; }
+        if(cap == nil or cap < 1) { continue; }
 
         title = tcell(fuelTable, "text", i+1, 0);
         title.set("label", tname);
@@ -546,7 +546,7 @@ showHelpDialog = func {
         return;
     }
 
-    dialog[name] = gui.Widget.new();
+    dialog[name] = Widget.new();
     dialog[name].set("layout", "vbox");
     dialog[name].set("default-padding", 0);
     dialog[name].set("name", name);