The generated font file still references Fyne v1. I don't know if this is intentional so I just want to share my finding with you.

In line 5 of font_gen.go:

import "fyne.io/fyne"

I like the app so far and it is a lot easier to make your own theme with it, so thanks a lot for making it!

I just discovered that the font selection for bold and bold italic is mixed up. You can also see it in the card widget titles. They are all italic. If you switch out the fonts manually and put a bold italic font in the selection for a bold font and the other way around it works properly.

Vs how the app starts:

Edit: But in the theme file it is correct. So I exported my theme file as shown in image 1 but the bold and bold italic fonts are mixed up. So the bug only seems to be in the ui.

Managed to somehow generate a theme that breaks the software it's used in and causes random white dialogues and boxes in a fyne app on random pc's

// Code generated by fyne-theme-generator

package gui

import (
	"image/color"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/theme"
)

type Theme struct{}

func (Theme) Color(c fyne.ThemeColorName, v fyne.ThemeVariant) color.Color {
	switch c {
	case theme.ColorNameBackground:
		return color.NRGBA{R: 0x30, G: 0x30, B: 0x30, A: 0xff}
	case theme.ColorNameButton:
		return color.Alpha16{A: 0x0}
	case theme.ColorNameDisabledButton:
		return color.NRGBA{R: 0x26, G: 0x26, B: 0x26, A: 0xff}
	case theme.ColorNameDisabled:
		return color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0x42}
	case theme.ColorNameError:
		return color.NRGBA{R: 0xf4, G: 0x43, B: 0x36, A: 0xff}
	case theme.ColorNameFocus:
		return color.NRGBA{R: 0x21, G: 0x96, B: 0xf3, A: 0x7f}
	case theme.ColorNameForeground:
		return color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff}
	case theme.ColorNameHover:
		return color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xf}
	case theme.ColorNameInputBackground:
		return color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0x19}
	case theme.ColorNamePlaceHolder:
		return color.NRGBA{R: 0xb2, G: 0xb2, B: 0xb2, A: 0xff}
	case theme.ColorNamePressed:
		return color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0x66}
	case theme.ColorNamePrimary:
		return color.NRGBA{R: 0x21, G: 0x96, B: 0xf3, A: 0xff}
	case theme.ColorNameScrollBar:
		return color.NRGBA{R: 0x0, G: 0x0, B: 0x0, A: 0x99}
	case theme.ColorNameShadow:
		return color.NRGBA{R: 0x0, G: 0x0, B: 0x0, A: 0x66}
	case theme.ColorNameSuccess:
		return color.NRGBA{R: 0x0, G: 0xf0, B: 0x0, A: 0x66}
	default:
		return theme.DefaultTheme().Color(c, v)
	}
}

func (Theme) Font(s fyne.TextStyle) fyne.Resource {
	if s.Monospace {
		return theme.DefaultTheme().Font(s)
	}
	if s.Bold {
		if s.Italic {
			return theme.DefaultTheme().Font(s)
		}
		return theme.DefaultTheme().Font(s)
	}
	if s.Italic {
		return theme.DefaultTheme().Font(s)
	}
	return theme.DefaultTheme().Font(s)
}

func (Theme) Icon(n fyne.ThemeIconName) fyne.Resource {
	return theme.DefaultTheme().Icon(n)
}

func (Theme) Size(s fyne.ThemeSizeName) float32 {
	switch s {
	case theme.SizeNameCaptionText:
		return 11
	case theme.SizeNameInlineIcon:
		return 20
	case theme.SizeNamePadding:
		return 2
	case theme.SizeNameScrollBar:
		return 16
	case theme.SizeNameScrollBarSmall:
		return 6
	case theme.SizeNameSeparatorThickness:
		return 0
	case theme.SizeNameText:
		return 14
	case theme.SizeNameInputBorder:
		return 2
	case theme.SizeNameInnerPadding:
		return 2
	default:
		return theme.DefaultTheme().Size(s)
	}
}

https://github.com/fyne-io/fyne/issues/3423

andydotxyz

Then I'm guessing the PCs that it doesn't work on have a different theme variant default (light vs dark) compared to your working PC. Your custom theme is missing some colours that the toolkit is providing - my guess is that ColorNameOverlayBackground would be most likely.