make ListHeader color independently customizable

ui/theme/theme.go

@@ -18,7 +18,10 @@ import (
 	"fyne.io/fyne/v2/theme"
 )
 
-const ColorNamePageBackground fyne.ThemeColorName = "PageBackground"
+const (
+	ColorNameListHeader     fyne.ThemeColorName = "ListHeader"
+	ColorNamePageBackground fyne.ThemeColorName = "PageBackground"
+)
 
 type AppearanceMode string
 
@@ -80,6 +83,8 @@ func (m *MyTheme) Color(name fyne.ThemeColorName, _ fyne.ThemeVariant) color.Col
 		defColors = m.defaultThemeFile.LightColors
 	}
 	switch name {
+	case ColorNameListHeader:
+		return colorOrDefault(colors.ListHeader, defColors.ListHeader, name, variant)
 	case ColorNamePageBackground:
 		return colorOrDefault(colors.PageBackground, defColors.PageBackground, name, variant)
 	case theme.ColorNameBackground:

ui/theme/themefile.go

@@ -32,6 +32,8 @@ type ThemeFile struct {
 type ThemeColors struct {
 	// Supersonic-specific colors
 
+	ListHeader string
+
 	PageBackground string
 
 	// Fyne colors

ui/widgets/listheader.go

@@ -62,7 +62,7 @@ func NewListHeader(cols []ListColumn, layout *layouts.ColumnsLayout) *ListHeader
 	for i := range l.columnVisible {
 		l.columnVisible[i] = true
 	}
-	l.container = container.NewMax(myTheme.NewThemedRectangle(theme.ColorNameBackground), l.columnsContainer)
+	l.container = container.NewMax(myTheme.NewThemedRectangle(myTheme.ColorNameListHeader), l.columnsContainer)
 	l.ExtendBaseWidget(l)
 	l.buildColumns()
 	return l