Hello Christian Surieux,
Thank you for this feedback. We are making some complex layout transformations in RadBook and this is maybe causing the slower rendering.
As for the mouse stolling - you should first identify where the problem comes from. You can try removing other components from the page to see when the page click will be faster and then we can see if there can be done, but we first should identify the problematic component (if such exist ofcourse).
the Telerik team