It's not so easy to answer your question. "Unknown source position" in the error message usually means the error doesn't lie in the source file included in the project, so the easiest place where to look is probably the easytab instrument. You could try attaching the source code to the instrument an enabling Break on Library error to look where the error arises, but unless you deep into the instrument source code, this information will probably be meaningless to you.
To investigate the possible causes, we sould have some notion of the operations you do on the easytab control: are you adding or deleting controls after the panels are added to easytab? Or are you modifying the callback of a control? Since the instrument chains its own callbacks to those define
d originally for panels and controls, these operations lead to several type of errors.
Try discarding the easytab control before quitting the program, the make sure the error lies in the easytab instrument and not elsewhere in the program.
Roberto
