Something that View->Debug Windows->Event Log uses?
Well, why can't you use RichMemo?
Actually i tried richmemo to install as component but lazarus gave a error code preparecreatewindow etc and i passed this step.
I recently make simple control.It may help you a little.
I get "project1.lpr(16,30) Error: Identifier not found "RequireDerivedFormResource" for this line RequireDerivedFormResource := True; in the project1.lpr file.what rev of lazarus does this your example made for?