private Dimension computeSize(Container target) {
          synchronized (target.getTreeLock()) {
             int hgap = getHgap();
             int vgap = getVgap();
             int w = target.getWidth();

             // Let this behave like a regular FlowLayout (single row)
             // if the container hasn't been assigned any size yet
             if (w == 0) {
                w = Integer.MAX_VALUE;
             }

             Insets insets = target.getInsets();
             if (insets == null){
                insets = new Insets(0, 0, 0, 0);
             }
             int reqdWidth = 0;

             int maxwidth = w - (insets.left + insets.right + hgap * 2);
             int n = target.getComponentCount();
             int x = 0;
             int y = insets.top + vgap; // FlowLayout starts by adding vgap, so do that here too.
             int rowHeight = 0;

             for (int i = 0; i < n; i++) {
                Component c = target.getComponent(i);
                if (c.isVisible()) {
                   Dimension d = c.getPreferredSize();
                   if ((x == 0) || ((x + d.width) <= maxwidth)) {
                      // fits in current row.
                      if (x > 0) {
                         x += hgap;
                      }
                      x += d.width;
                      rowHeight = Math.max(rowHeight, d.height);
                   }
                   else {
                      // Start of new row
                      x = d.width;
                      y += vgap + rowHeight;
                      rowHeight = d.height;
                   }
                   reqdWidth = Math.max(reqdWidth, x);
                }
             }
             y += rowHeight;
             y += insets.bottom;
             return new Dimension(reqdWidth+insets.left+insets.right, y);
          }
       }