Hi,

1.- Is everything I will draw going to be drawn using the multibuffer feature?

Just if you draw inside a WM_PAINT case. Anything drawn outside will be displayed directly, or not even displayed since it gets overdrawn by the window manager. Anyway, drawing outside WM_PAINT is not recomended when using the window manager.

2.- Can I select in which back buffer will it be drawn?

No unfortunately not. This is done automatically by the window manager.

3.- Will each drawing operation be drawn one by one or can I choose to draw several things to appear together at the same time?

They are getting displayed all at once. Before the window manager starts the drawing process it tells the multibuffer module to copy the front buffer into the backbuffer. After all drawing operations are finished the backbuffer become the front buffer and all drawings are getting displayed at once.

What I mean with the last question is that if I want to change the front
buffer from one with just one button to another one with 5 buttons,
will each button be drawn one by one or will they appear at the same
time?

I guess what you mean are virtual screens. Multibuffering is to avoid tearing effects and to some point flickering. Unfortunately virtual screens and multibuffering is not compatible to each other.

When using multibuffering you can create windows outside the visible area (or create them when required) and make them visible on button press.
For example you have one button and on button press you create another window which holds five other buttons. Those buttons will appear all at once when their parent window gets visible. Take a look into the example attached.

Regards,
Sven