Concerning the value of ATTR_TASKBAR_BUTTON_VISIBLE, are you minimizing your panels from the main thread, or from a secondary thread?
The value of ATTR_TASKBAR_BUTTON_VISIBLE is thread-specific. You can change its value in any thread, but it only affects that thread and no others. The main thread uses TRUE as the default for this attribute (so setting it to TRUE at the top of main will have no impact) but any other thread uses FALSE as the default. If you are minimizing your panels from one of these other threads, that would explain why it's set to FALSE.
Luis
