Thanks.
I'm referring to main.xml, not a new screen.
I am new to Eclipse, so I may not be using it correctly. Pardon me for being a noob.
According to the manual:
"The palette can also be opened in its own view using Window > Show View > Palette."
So I did that while at the very beginning of a newly created project. The Eclipse layout palette was displayed by default. Another palette window opened up with this message "A palette is not available."
Why is the Sketcher palette unavailable for the main.xml?