[Refactor] Fix for bitflags with only one checked option

Resolves #51.  Using setCurrentIndex on bitflag enums causes the
QComboBox to break when only one option is selected. It returns
something other than -1 and in doing so checked option's UI is inactive.

src/nifdelegate.cpp

@@ -251,7 +251,18 @@ class NifDelegate : public QItemDelegate
  }
 
  cedit->setEditText( NifValue::enumOptionName( t, value ) );
- cedit->setCurrentIndex( cedit->findText( NifValue::enumOptionName( t, value ) ) );
+
+ if ( eo.t == NifValue::eFlags ) {
+ // Using setCurrentIndex on bitflag enums causes the QComboBox
+ // to break when only one option is selected. It returns something
+ // other than -1 and in doing so checked option's UI is inactive.
+ // See: https://github.com/niftools/nifskope/issues/51
+ cedit->setCurrentIndex( -1 );
+ } else {
+ cedit->setCurrentIndex( cedit->findText( NifValue::enumOptionName( t, value ) ) );
+ }
+
+
  } else if ( ledit ) {
  ledit->setText( v.toString() );
  }