Hi Parimal,
1. This is the default behavior of the RadDock control. All of the <iframes> on the page become invisible when a RadDock is dragged due to the fact that the dock's events are not fired correctly (i.e. they are not fired in the page but in the <iframe>) under some of the browsers when the dock is moved over an <iframe>. You can observe that the dock is not behaving as it should when dragging it over an <iframe> under Firefox. However if you still want to show the <iframe>s here is a way to make them visible all of the time:
2. The RadDock uses jQuery animations, and in the project that I tested they are working fine. Please find it attached to the thread. Can you please open a new support ticket and send us a sample running project where this issue can be observed? Once we receive it we will do our best to provide a working solution.
Greetings,
Pero
the Telerik team