Android Question The actionbar UpIndicator is not useable in andorid 5.0

My code:
Dim acBar As StdActionBar
acBar.Initialize("acBar")
acBar.Icon=LoadBitmap(File.DirAssets,"ic_action_user.png")
acBar.ShowUpIndicator=True

The UpIndicator can click and run normally on android 4.0/4.4,But on android 5.0 , the click listener cant work,the code is :

Sub acBar_ButtonClicked
StartActivity(Main)
thisActivity.Finish
End Sub