When refresh() is called, I dispose the children of the parent-composite.
First I always tried to find a method like parent.clear() or
parent.removeAll(), but there`s no method like that.
It works this way:
Control[] controls = thisParent.getChildren();
for(int i=0; i<controls.length; i++) {
Control c = controls[i];
c.dispose();
}
After that I can draw all the vehicles new.
And then there is another important thing: In some cases the new drawn
children weren`t visible.
I found out what to do: After the new draw I do this:
thisParent.layout(true);