Apps Mock Preview Not Showing in Eclipse

[markmccabe]

I'm a newbie and experimenting with Eclipse, I use a Mac OS.

I have followed several different tutorials and keep experiencing the same problem.
I can't seem to get the preview or mock up of the android phone to appear, its where you drag and drop the buttons and widgets.

Even the palette options aren't showing - can anyone help it is driving me mad?

 

[BetterAndBetter]

Any errors displaying?
Maybe change target sdk version for preview (for example: you developing on API version 20 but eclipse can render preview only for version 19)