12. FAQ o Win API

Q> How to make that a window did not appear on таскбаре? 
A>

There is more than one way to stop a window appearing on the taskbar. 

Rather than WS_EX_APPWINDOW, give your window the WS_EX_TOOLWINDOW extended 
style. Since toolbars do not appear on the taskbar, this will prevent it 
appearing there. Unfortunately, this has some rather negative repercussions  
on the appearance of your window: it gets a thin caption with smaller title, 
and loses its system menu. This is not acceptable to many people. 

Windows owned by an invisible window will not appear on the taskbar. "Great", 
say you, "but my app is dialog based, so what now Mr Smarty?". Well, you can  
either recast your dialog app as an SDI with a hidden main window, and have  
that main window shown at startup, or you can create your own hidden window  
and set that as your dialogs owner.