add tree models (tagtraa, dumpviewtree) onlywhen the tree is visible, better preserving the expanded states of the tree nodes

libsrc/ffdec_lib/src/com/jpexs/decompiler/flash/tags/Tag.java

@@ -343,6 +343,9 @@ public abstract class Tag implements NeedsCharacters, Exportable, ContainerItem,
      */
     @Override
     public String toString() {
+        if (getName().equals("DefineSprite (406)")) {
+            int a = 1;
+        }
         return getName();
     }