This is very strange story.
We need window fits screen. Display resolution in our project settings - 1400x960. But other devices have different screen resolutions, so we need correct size for gui nodes manually in code.
First of all, we use obvious solution:
node_size = 1400
But this not work. Node is smaller than screen (or bigger)!
Okay, what we do next?
node_size = render.get_window_width()
gui.set_size(node,node_size)
Not work too!
What we doing wrong?