I wonder how can i hide the attached panel in a way that only the red button to be shown on the left side of the browser’s window and when i click on the red button to appear the whole panel. If i click again on the red button, the panel to disappear again on the left side of the browser’s window?

I know i should use absolute positioning related to a relative positioned wrapper div, but that’s all my idea…
<div class="wrapper"><div id="panel"></div><!-- #panel --><p>content</p></div><!-- .wrapper -->
.wrapper {position: relative; margin: 0 auto; width: 800px; height: 500px;}
#panel {position: absolute; left: -150px; top: 50px;}
Here is a very simple example, it uses the animate() function to handle the showing and hiding:
jQuery:
Working Demo Available here
CSS (from demo):
Related HTML: