With this XAML:
<Page.BottomAppBar>
<AppBar x:Name="bottomAppBar" Padding="10,0,10,0">
<Grid>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Left">
<Button Style="{StaticResource BrowsePhotosAppBarButtonStyle}" Click="btnOpenImgFiles_Click"/>
<Button Style="{StaticResource OpenAppBarButtonStyle}" Click="btnOpenMap_Click"/>
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
<Button Style="{StaticResource SaveAppBarButtonStyle}" Click="btnSaveMap_Click"/>
</StackPanel>
</Grid>
</AppBar>
</Page.BottomAppBar>
(which I adapted from markup I found online) I got a "Windows.UI.Xaml.Markup.XamlParseException"
Looking at this, I figured it should be AppBarButton instead of Button, so I changed them to that...but I'm still getting the same err msg. Is it because there's no such thing as "BrowsePhotosAppBarButtonStyle" (I can't find a list of valid values for that) or...???