It worked once, but in a wrong place. I changed some container size flags, and now it’s been 3 hours since all went wrong(

The problem:
I have NinePatchRect (1) inside another NinePatchRect (2) inside GridContainer. I need to pass outer (2) rect’s size to the inner (1) one. Both NinePatchRects have textures set at runtime. As I’m working within a container the only way to get starting size would be to set an anchor for (2), otherwise the size would equal to (0, 0). And I can actually see the size.x value change in the editor after assigning the anchors. BUT, once the code is executed, by the time I get to the size.x value it becomes 0. Even though the texture is placed and shown correctly.

NPR (2) has following size flags:
Horizontal Fill Expand
Vertical Fill

NPR (1) is set to layout_mode POSITION at the position of NPR (2). If I use any anchors, I won’t be able to change the size of the rect (which I need to do dynamically).

I actually have a RichTextLabel (of the same size I could use) nearby within the same GridContainer, and I can’t get it’s size value as well, as it turns to (0, 0).

Question:
How do I get the size of GridContainer‘s child?