Resolve tdf#124572 - Draw a faint line between tabs

Change-Id: I6cbbefe1cb16599ae81fc6dcb5a51ef1ca2db6f6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/128407
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <heiko.tietze@documentfoundation.org>
diff --git a/svtools/source/control/tabbar.cxx b/svtools/source/control/tabbar.cxx
index e910473..a62d0ae 100644
--- a/svtools/source/control/tabbar.cxx
+++ b/svtools/source/control/tabbar.cxx
@@ -137,10 +137,21 @@ public:
        mrRenderContext.DrawRect(maLineRect);
    }

    void drawSeparator()
    {
        const tools::Long cMargin = 5;
        const tools::Long aRight( maRect.Right() - 1 );
        mrRenderContext.SetLineColor(mrStyleSettings.GetShadowColor());
        mrRenderContext.DrawLine(Point(aRight, maRect.Top() + cMargin),
                                 Point(aRight, maRect.Bottom() - cMargin));
    }

    void drawTab()
    {
        drawOuterFrame();
        drawColorLine();
        if (!mbSelected && !mbCustomColored)
            drawSeparator();
        if (mbProtect)
        {
            BitmapEx aBitmap(BMP_TAB_LOCK);