The VisibleOnPageLoad property should not be used for this
purpose. It is a behavior property which will result in the RadWindow opening
every time the page is post back.
Quite often the VisibleOnPageLoad property gets set to true
while the intention is that the RadWindow should only show once. Doing so will
result in the RadWindow reopening if a postback is initiated from another
element from the page, which is rarely the desired behavior. Also, this
approach will not work in case this happens in an AJAX request and the
RadWindow is not included in the partial page update.
There are several ways to work around this:
2) Reset the VisibleOnPageLoad property to false with code when suitable, depending on the particular scenario
3) Set EnableViewState to false for the RadWindowManager that contains the desired RadWindows