Thanks for adding Ctrl-Up / Ctrl-Down for top / bottom of RadGridView as standard features in Q3 2009.
a) I would've preferred you add it as an "option" such that if the option were "on" (True or "off" / False - call it what and default it how you want), it would performed the standard behavior of top / bottom of RadGridView, otherwise it would do nothing except be passed to the KeyDown Event. Just like in the movies, there should always be a "manual override". ;)
b) In the Q2 2009 (2009.2.9.729), the work around you provided goes to the top / bottom of the current Master / Child GridViewTemplate. In Q3 2009, both the workaround (if enabled) and the built-in behavior goes to the top / bottom of the whole MasterGridViewTemplate. I think it would be more useful to simply go to the top / bottom of the current Master / Child GridViewTemplate. If the user wants to proceed further, he would still have the option to subsequently press Up / Down Arrow followed by Ctrl-Up / Ctrl-Down again, repeatedly until he gets to the top / bottom of whatever level of Master / Child GridViewTemplate he wants. With the other way, he has no choice.
d) It looks in both cases (in item b), this is the result of Telerik changing the behavior of the SelectNextRow and SelectLastRow methods which is either an unintentional "bug" or an undocumented intentional "Breaking change".
e) If it is a undocumented intentional "Breaking change", I can sort of see an argument for, but I no longer have an easy way to manually implement the old behavior because RadGridView.CurrentRow.ViewInfo.CurrentIndex, since Q3 2009, is always returning 0 vs. the 0-based index of the CurrentRow relative to the Current Expanded GridViewTemplate (which I've reported in http://www.telerik.com/community/forums/winforms/gridview/expand-colllapse-master-parent-childgridviewtemplates-programmatically-in-radgridview.aspx
f) An additional option would be to implement Ctrl-Shift-Home / Ctrl-Shift-End keys as the top / bottom of the whole MasterGridViewTemplate so you can continue letting Ctrl-Up / Ctrl-Down be top / bottom of the current Master / Child GridViewTemplate.
b and f obviously wouldn't apply in .Net's DataGridView that I based the original suggestion on because it doesn't have hierarchical sub-grids, but they are logical evolutions of the keys that were in DataGridView for a grid that does have hierarchical sub-grids.
Telerik WinForms 2009Q3 (2009.3.9.1103), VB, VS 2005 (v8.0.50727.762 SP.050727-7600), .Net 2.0 (2.0.50727), XP SP3, 3GB, 2.99GHZ, Core2Duo.