How to resize a custom control inside a container?

Godot Version

4.3.stabe.mono.official

Question

I have a scene which is a custom control for a button. It is supposed to be 3 layers: texture rect, texture rect and semi transparent button on top.

I want to put this control as an item inside HBoxContainer. However, its size is very large, and I can not understand, what controls the size and how to change it. Is it determined by the texture size?

Apparently, can’t put more than one screenshot in a post, so here is the main scene (should have been part of the question):