Turbine.UI.Lotro.Window:SetResizable(true) !
 

I just stumbled across this method when debugging. It works too, and very nicely :)

Turbine.UI.Lotro.Window:SetResizable(true)

I can get rid of the manual coding for this. I bet its a lot faster too. It also nicely handles the cursor changes etc.

Yep. This is also inherited by the Turbine.UI.Lotro.GoldWindow class along with the new :IsResizable() method.

I have noticed some odd behavior when dragging the bottom left corner to the left, sometimes it moves the window instead of resizing it. Other than that, it works quite nicely. I haven't really noticed any speed difference over using the MouseDown, MouseMove, MouseUp events to manually implement resizing but it is wayyyy simpler plus as you pointed out, the pointer icon is automatically handled.

Now if only Turbine would give us a way to set the mouse pointer icon so we can manually implement resizing for the Turbine.UI.Window class...