1. Why does only a few objects support the OffsetX-Y command?
Don't know.
2. Is it possible to have change only the color of the title/header of the ActionWindow?
if yes => command please ^^
If you mean "can it change colour depending on status or type of window being shown" the answer is "No". I'm 99% certain you can create an action window header graphic and specify that the action window only use the header, with the background colour specified in the XML. I'm short on time here atm, but have a look at the xml file for the Noire skin as I think it uses this technique.
3. Is it possible to remove the arrows of the splitter and only have a 1px width splitter?
It's possible. I know because I managed it when I created the iCopy 9 skin, I just can't remember off the cuff how I did it. I will report back later. I should say though, that it was not very well received. It looked neat, but was nigh on impossible to hit with the mouse, which got on peoples' nerves!!
4. Is it possible to remove the two equilizers in the display?
This is a per-user setting, chosen by left or right click in the player display area. It is not possible to force the choice on the user.
5. Also i don't really understand the margins command, but i will later give you an example, maybe someone can discribe it better than the tutorial ^^
Imagine a MainFrame_TopBorder.png file with a 150 pixel graphic inset on the left end. You do not want the skinning engine to stretch this graphic, not ever. With MC maximised on my monitor, for example, the TopBorder file must be stretched over 1920 pixels. If you set the margins in the xml for the top border file to something like
Margins="200,1,1,1" then the skinning engine will draw the first 200 pixels of the top border file as they are, then stretch the rest to fill the 1920 pixels. The margin values are applied in the following order:
Margins="
Left Margin,
Top Margin,
Right Margin,
Bottom Margin"
-marko