Thanks for this very useful mod, first of all. This bug is a bit of a nitpick. :)
I often play Factorio on the right half of my monitor, with a browser on the left half. It seems like the width of Simple Notepad's window is dependent on the width of the Factorio window. I suppose that is fine, to make sure it fits on the screen. But the textfield on the narrow version of Simple Notepad is smaller than the window itself. See screenshot: https://imgur.com/a/KBnImwB.
[edit] I didn't realize I could choose the Bug category, my bad.
