Cannot assign to non-existent property "states"

[Zunneh]

Hi guys , i copy this program from tutorial in internet and there is a problem "Cannot assign to non-existent property "states" i think the problem came from window , how i can solve this thanks :
P.S: the error is in line 49

[dheerendra]

states property comes from Item. Window is not inherited from Item. Put all the state information inside the rectangle. It should solve the problem.

[Zunneh]

@dheerendra it solve my problem , thanks dude :)