You have put your RadSplitter inside of TABLE, TR and TD elements which does not have explicit height set and this breaks the following rule:
If a web page element has its height defined in percent, its parent element must have a height style as well. The rule applies recursively.
You can read about this rule on the W3 site (http://www.w3.org/TR/CSS21/visudet.html#the-height-property):
Specifies a percentage height. The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly (i.e., it depends on content height), and this element is not absolutely positioned, the value computes to 'auto'. A percentage height on the root element is relative to the initial containing block. "
You can refer to this online article (http://demos.telerik.com/aspnet-ajax/Splitter/Examples/ResizeWithWindow/DefaultCS.aspx) for information as well.
What I can suggest is to simply remove the whole TABLE - if you need to use a header and a footer, use the HeightIOffset property as explained below:
I hope that my suggestion helps, in case you need further assistance, let me know and I will do my bets to help.
the Telerik team
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