Which part of widget need to render, e.g. if it is a button then PartDraws.left tell that only left side and center will be rendered, this need for grouping rendering of widgets.
As example consider this layout of grouping: button2|button3|button4
for button1 PartDraws will be left, for button2 and button3 center and for button4 it will be right.
Draw all parts - left, center and right.
See Implementation
Which part of widget need to render, e.g. if it is a button then PartDraws.left tell that only left side and center will be rendered, this need for grouping rendering of widgets.
As example consider this layout of grouping: button2|button3|button4
for button1 PartDraws will be left, for button2 and button3 center and for button4 it will be right.