Problems with using TAB on editing forms in Admin Console

There are 2 ways of switching between different fields, when filling-in the large forms:

• using TAB button
• using Mouse left button
  TAB button way is pretty handy and especially, when you need to fill all fields from top to bottom.

However I've noticed, that TAB behavior has changed, since In-Portal 5.1.1 due form element definition simplification. As a side effect the "tabindex" parameter of the first field became empty - tabindex="", instead of tabindex="1" as before.