Viewport catches mouse events despite being under Canvas Layer

[haaldor]

Godot version:

3.2.3.stable.official

OS/device including version:

GPU: GeForce GTX 1060 6GB
Using GLES2, happens on GLES3 as well.

Issue description:

What happened:

When using Viewport to draw world and CanvasLayer to draw overlay, controls in Viewport are catching mouse input events despite being drawn under overlay.

What is expected:

Canvas layer should be one catching mouse events, as it is drawn on top.

Steps to reproduce:

1. Create new project
2. Add nodes as following:

- Node2D
-- Viewport Container (set rect_size to window size, f.e. 1024/600 )
--- Viewport (set size to match parent's rect_size)
---- Button (can add script to print something on pressed() signal to check it)
-- Canvas Layer
--- LineEdit

3. Save and play. LineEdit is not getting any inputs on where button is, despite being drawn over the button

Minimal reproduction project:

Viewport_canvas_layer_bug.zip

[akien-mga]

Duplicate of #39666