Please note that you have a Panel with two children. Now, if you set setWidth("*") for both descendants, then the first child will accept the required width, and the second will receive all that remains.
If you set setWidth("60%") for the first child and setWidth("*") for the second child, then the first child will take 60% of the panel width, and the second child will receive the remaining 40%.
.setWidth100(); and .setHeight100(); these 2 cause the component to fill the canvas in which it is located. This is the average width and height of 100%, which is equivalent to setWidth("100%") and setHeight("100%") respectively.
This is usually used when you specifically do not want to set the width of the child panel. You specify the coarse width of the first child panel and automatically set the width of the second child.
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