For weeks now I have problems in a splitter full page scenario, you can see this on my posts in this forum 
And I follow your suggestens and fix a few problems, but I think that I found the bad component in this hole splitter, panel, tab and chart scenario!
It is the tabcontrol!
Here my html and js code (Without your component, don’t know how to add this on jsfiddle)
http://jsfiddle.net/NoiZy/BAmJB/
The problem is, the tabcontrol don’t respect 100% of parent container!
You will see that tabcontrol width is wrong and destroy the hole page.
Kind regards
PS: “” into your panel with the id=”rightside-panel” and it have the perfect width!
So the problem is defenitly in your tab component.