Older Valence file maintenance apps created through Nitro AutoCode can sometimes exhibit a display problem upon migration to Valence 5.1.  This can also be true for AutoCode-based file maintenance apps created in 5.1 builds prior to 5.1.20171202.0.  The most common symptom is that a portion of the edit/add window displays outside of the portal boundary, as shown here.

AutoCode apps generated with Valence 4.2 use Ext JS 4.2 -- the fact that these are the same version numbers iwherever possible it is recommended that you just regenerate the app using the new autocode that comes with valence 5.  However, if you've made enhancements to AutoCode apps generated in Valence 4.2 then regeneration from scratch isn't a very viable option.