Android Question Basic Layout not working

[solfinker]

Hello!
I must be making a basic mistake, but I cannot tell.
I do not know why the button appears to the left in some devices

Thank you

 

[solfinker]

Well, I am using a panel and the button is anchored right(10) and top(10) to it

 

[solfinker]

I've found my mistake: I had two variants