Events of TabControl

HI 
In c:DuctilCAD_DuctilCAD_MainForm_TabControl24_OnChanged the return of Ferramentas is 0 the return of Configurações is 1
 
In c:DuctilCAD_DuctilCAD_MainForm_TabControl24_OnSelChangingo return of Ferramentas is 1 and the return of Configurações is 0 
 
Does this difference exist a difference or that is a BUG?

The nSelIndex argument of the OnSelChanging event handler is the index of the tab that is current before the change. For the OnChanged event handler, nSelIndex is the newly activated tab index.