Applied visiblity to hide sprite as opposed to negative src_rect.y

Data/Scripts/012_Battle/005_Battle scene/005_PokeBattle_SceneMenus.rb

@@ -414,12 +414,14 @@ class FightMenuDisplay < BattleMenuBase
   def refreshMegaEvolutionButton
     return if !USE_GRAPHICS
     @megaButton.src_rect.y    = (@mode - 1) * @megaEvoBitmap.height / 2
+    @visibility["megaButton"] = @mode > 0
     @megaButton.z             = self.z - 1
   end
 
   def refreshShiftButton
     return if !USE_GRAPHICS
     @shiftButton.src_rect.y    = (@shiftMode - 1) * @shiftBitmap.height
+    @visibility["shiftButton"] = @shiftMode > 0
     @shiftButton.z             = self.z - 1
   end