The partialRoot component lets you designate areas of a UIX XML page as partially updateable even if you don't have a body element in the page.
To enable partial rendering, the partialRoot must be added at the root of the UIX XML node hierarchy, above any partial targets which generate content, or any nodes that generate partial events. There may be multiple partialRoot blocks on a page.
Using PartialRoot
Working with Simple and Miscellaneous Components
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