Thread-safety note
The current component version is not thread safe. But if you need to use it in a multi-thread
application, the following hint should help to use it right. For example, you need
to call Open method from several threads. Don't do this, instead do it in message way:
all threads should send a message (it may be some Windows message not used in your application,
e.g. EM_DISPLAYBAND) to main thread, informing it that a filename should be opened.
Pointer to a filename can be passed as message parameter.
So the main message handler calls Open.
Note: this may be a risk of receiving messages from several threads at almost the same time,
so additional boolean "Busy flag" should be set on message-handler start and reset on exit.