Enlarging NavigationView's TogglePaneButton

[JGKle]

Forgive what I'm sure is a dumb question - I'm still new to styling in Avalonia.

I can't for the life of me figure out how to enlarge the NavigationView's TogglePaneButton. When I use the inspector, setting the height/width/fontsize yields no change; likewise if I drill all the way down to the TextBlock that shows the icon & try to set the font size there.

I did find that if I enlarge the Border directly inside the TogglePaneButton, the clickable area does increase (but not the icon of course). However, even that I'm having trouble doing with styles:

<Grid.Styles>
  <Style Selector="Button.TogglePaneButton Border">
    <Setter Property="Width" Value="50"/>
    <Setter Property="Height" Value="50"/>
  </Style>
</Grid.Styles>

The default size feels pretty small & hard to tap on mobile screens. I'm sure I'm missing an easy way to do this...any help would be appreciated

[JGKle]

....Anyone? 🙏

[JGKle]

NavigationBackButtonWidth doesn't seem to be it. To clarify, I'm referring to this:

Even if I directly edit FluentAvalonia/Styling/ControlThemes/FAControls/NavigationView/NavigationViewBackButtonStyles.axaml in the sample app & edit NavigationBackButtonWidth, the size of that button doesn't change. Using the inspector, I think it's the TogglePaneButton, per the OP. But no matter what I tweak I can't get the button indicated above to increase in size.

[JGKle]

...Anyone: 🙏

[timunie]

please use DevTools via F12 and explore the given ControlTheme I linked above.

[JGKle]

I did - that's what I meant by Using the inspector, I think it's the TogglePaneButton, per the OP. That's how I found TogglePaneButton. Whatever I tried I couldn't figure out anything that worked.

[JGKle]

For what it's worth, I also spent 3 hours with various agentic coding tools, given them full access to the FluentAvalonia source, and none were able to resize the button (tried Claude Code, OpenHands, and Aider). That mirrored my experience.

I'm trying to get the button to fill the top bar, like this:

whereas by default it's like this:

Still stuck to no avail. I just don't see how it can be done with the response you gave above :(