Hi hahr!
First of all, if you want to write in spanish feel free to do so, I can write and read spanish too.
The problem you have right now seems like a timing problem, the refreshing of the user interface is what is causing the problem as you said so we are gonna need to change that a little bit.
By any chance can you post your project so I can reproduce the problem?
That would be faster than trying to guess.
I hope you can do this, if not, let me know and ill post some general links for you!
Have a great day!! 🙂