I think the BoxLayouts aren't working like you want. Just leave them out and let the default SpringGridLayout work for you.
With your current approach, you will also have the problem that your columns won't line up.
Make one container and add the Options label and another container to it...
Container window = new Container();
Container form = window.addChild(new Container());
// Then for each row you in the "form":
form.addChild(new Label("My Label")); // automatically adds a new row
myTextField = form.addChild(new TextField(""), 1); // the ending 1 will put it in the second column of the current row
You could also do it all explicitly stating each row and column but that's a pain.
You can see any of a half-dozen examples of this in various pieces of my open source code.
If you search around in these projects you are bound to find hundreds of examples: