Docking

To dock a control inside its parent use d or dock key. When docking a control, the following keys can not be used: align, x, y, left, right, top, bottom. Width and height should be used to specify the size of control. If not specified, they are defaulted to 100%.

LayoutOutcome
d:c,w:30,h:50%
d:bl,w:50%As height is not specified, it will be defaulted to 100%

d:c or d:tl or d:br
or any dock without width and height parameter
As both width and height parameters are missing, they will be defaulted to 100%. This means that current control will ocupy its entire parent surface. This is the easyest way to make a control fill all of its parent surface.