Point & click Shader in a viewport implementation troubles

I have a PSX shader downloaded, but i dont really know how to implement it in game right. I am using Godot 4.2

On the 1st screenshot, you see the subviewport container & the subview port with the shader applied to the container. The camera is stored in the subviewport. The shader works perfectly, but the game breaks! Since its point & click, no controls work (even after the setting “ignore” parameter in the container), except for the buttons on the keyboard.

On the 2nd screenshot it shows how it was functioning before adding the shader. Everything is clickable & works.

On the 3rd screenshot I’ve tried instancing the main scene in a viewport scene which contains the shader, but still no response. How can I make my game work like it used to, and moreover, how can I apply the shader between multiple scenes? Do I have to do the instancing like on the 3rd screenshot for each scene, or there are other ways?

Basically the cursor cant even enter the project it seems…