Global Border Style Causes Unexpected Borders in DataGrid Column Headers

[luckyandy0714]

Bug explanation

When I added a global Border style in App.xaml:

It caused unexpected borders to appear at both ends of the DataGrid's ColumnHeader:

I tried adjusting any possible Border settings within the DataGrid, such as modifying the BorderThickness of the DataGridColumnHeader, but none of them worked.
I'm not sure if this is a bug or if there's another setting that can override the DataGrid's internal borders to prevent them from being affected by the global Border style.

Version

5.2.1

[corvinsz]

@luckyandy0714 defining a global implicit style for basic controls like the Border is not a good idea.
Amongst other controls - like Grids - Borders are used almost everywhere within the MDIX styles.

Your best bet is probably to give the style an x:Key and reference it via the key whenever you need it. If applicable you can then also set the style as a implicit style at a more deeper level (rather than the app level), e.g.:

<UserControl ...>
    <UserControl.Resources>
        <Style TargetType="{x:Type Border}" BasedOn="{StaticResource MyCustomBorderStyle}"/>
    </UserControl.Resources>
    ...
</UserControl>