Some java application have it’s own title bar and buttons such as close, maximize, minimize. And I set the style NoTitle for this application. But it has no affect to the child window such as the open, save dialog.
Is there a way to apply style NoTitle for all child window of the specific application, and keep other applications with normal style?
Not really. Generally you match style settings to other attributes of the window like class and resource. You could inspect the attributes of the children to see if there is something you can match off. Use either FvwmIdent or xprop and target a child window. You might be able to match off something there such as the window title or class (WM_CLASS).