Is it a bug?
1. On Lazarus, start a new application project
2. Go to Custom Drawn component palette and select TCDTabControl
3. Put the TCDTabControl on the form
You cannot select it by clicking, you cannot resize it by using mouse. If you force deleting it, you sometimes will get "Access violation" error. Similar issue happens on TCDPageControl too.
Tested on both Lazarus 1.6.4 and 1.8.0RC5 Linux 64 Gtk2.