In any Silverlight project you can hover your mouse over the edges of the Grid and click it.

You can drag and drop multiple controls inside this Row or Column. Let's say, you get a grid split something like this…

If you like you can resize the cell size. But, it can be a good idea to go "Auto". if you hover your mouse near the cell's left edge, you will get a choice like the following… (for fixed, proportion and Auto).

If you click Auto, you will find the size automatically getting adjusted. Works pretty well with appropriate margins set!

Notice that button's bottom aligns with the Row's bottom. Top and Left are still using Margin, and hence they aren't disturbed. Try it out, if you haven't already.

Cheers,
Rahul

Quote of the day:
Even if you do learn to speak correct English, whom are you going to speak it to? - Clarence Darrow