The resizing process which is observed is due to RadSplitter calculating its size relatively to the browser window. If you do not want to observe the resizing process I could suggest you set the VisibleDuringInit property of the corresponding splitter to false in order to avoid the undesired effect which occurs while the page loads and the RadSplitter gets initialized.
Please, describe in more details what is the behavior you observe when there is and when there isn't a RadDockLayout in your masterform and what is the behavior you expect.
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