Thank you for evaluating our components.
Regarding your issues:
1. The preview drop hints in RadDock are heuristic and may not give you the actual size the dropped window will occupy until the actual layout is executed. Using our RadSplitContainer, one may achieve some really complex layout scenarios and hence size estimation is not exact. What we may do in future releases is to estimate the size with more closer approximation.
2. This was a known issue with the release you are using and this issue has already been fixed in an internal build. We are also very close to our next release - Q3 2009, which fixes other known issues as well and adds lots of useful features to RadDock.
Thank you for your time and feedback.
the Telerik team