I found an old bug report for this behaviour/bug, but the problem is still here.
Drawing was totally messed up when focus is on a NextInspector-object. Items were painted using graphics from other parts of the form. Graphics were wrong even at design-time when working with the object.
DoubleBuffered was set to TRUE on the object. It is not a published property, so it is not visible in the object inspetor. I had to view the form as text to locate the difference in-betwean a well behavied instance and a faulty one.
Please add some code to give us users a warning at least at designtime when DoubleBuffered is set to TRUE. I spent a lot of hours hunting down this error.
Read on previous report that Raize Components ( now Konopka Signature Controls) are setting the property to TRUE. I am using them, so this is probabl why I got the problem.