How to make my cairo-dock icons not to hide(always shown).
Cairo Dock (Docky) is a great alternative to the Unity panel. Docky is highly customizable, and the possibilities are almost endless.
As to your question, there are tons of resources out there to show you how to do this and other cool things. Here are a few that I have encountered recently (I intentionally selected sites with a broader appeal to benefit other surfers):
1) First, a basic tutorial (GLX-DOCK is chockablock with tips and hints.Look around!) http://glx-dock.org/ww_page.php?p=A%20complete%20tutorial%20on%20how%20to%20customize%20your%20dock&lang=en
2) This one steps you through some cool Ubuntu deskop facelifts with Docky: http://mylinuxexplore.blogspot.co.il/2013/02/simple-steps-to-decorate-linux-desktop.html
3) Here's another sub-site of askubuntu, dedicated to hot Cairo Dock questions: http://askubuntu.com/tags/cairo-dock/hot
Have a ball.
That way, your dock will always be on top of any window.