UI Masking in worldspace

Hello everyone, this is the first time I ask a question on the forums and I hope you can help me.

I'm currently developing a "windows-like" computer system for a narrative game. The screen is a canvas in worldspace put against the computer screen mesh. My problem is I need to mask the windows if they go past the boundaries of that canvas so they don't just appear outside of the PC screen. I've seen people use Mask and Rect Mask components but it doesn't seem to work in worldspace. My question is: am I doing this wrong or is there a workaround to make the masks work in my setting ?

Thanks in advance !