"Create Library" window is broken

[NotArme]

Material Maker version:
Issues found both on oficial 1.4a and latest release from master

OS/device including version:
Windows 11

Issue description:

• Window that pops-up when creating a library cannot be closed with the usual X button

• Prompt for library selection is labeled Library file, but the button is click to open a path, making it not clear whether i'm supposed to choose a file or path (I think it should be a path)

• When clicking the button, the file select screen opens up on fullscreen, and it keeps flashing black (could not capture that issue on the video)

• The file select screens asks for a json file instead of a path, so it's impossible to create a new library without manually creating an empty .json file first

• This last one isn't a bug, but it would be nice to be able to input the file creation path as a string without having to use the file select button, example from blender:
  

Steps to reproduce:

Screen.Recording.2024-11-28.195512.mp4