step 7
Apply a final drop shadow to the rectangle to help it “float” above the background
The Final Result
Your Aero taskbar should look something like this.
adding icons
If you want to add an app icon, use a shadow, with adequate spacing.
By The Oxygen Team, KDE; - KDE github;, LGPL, https://commons.wikimedia.org/w/index.php?curid=18610546, https://commons.wikimedia.org/w/index.php?curid=18610562