Hello Alexander,
I suppose the problem occurs because your tested application was compiled with debug information incorrectly. Please make sure that you have compiled the application by following the instructions given in the help topic I mentioned. Pay attention to the fact that your application must be compiled without optimization.
I have attached a simple application containing the TCheckListBox control. I was able to check whether the item is checked by using the wSelected property. Can you access this property?
If the problem persists, please let me know what IDE was used to create your application.
