The best approach that I would recommend is to place the RadToolBar and the RadGrid control in a RadMultiPage
with the respective RadPageView. Thus, they will load with the RadPageView that is assigned to the RadTab. However, if you explicitly need to insert them on clicking of the tab you could use the TabClick
server-side event or the OnClientTabSelecting
client-side event depending on your requirements.
the Telerik team