JTree Button, Line and Java look and feel ?

Question

Hi all,
I have 3 small problem with my JTree ..
1) The 'expand' button size ...
I set a different Icon for each node in a getTreeCellRendererComponent method (from a class that extends DefaultTreeCellRenderer )...
The icon are 32x32 pixels.. .and the RowHeight and the Font have been changed too. .
How to change the size of the expand button (+/-) near the text node ? Because on my JTree, the expand/collapse buttons are really small compare to the icon & row height.
2) No line appear between the node ...
I try to set the line style property with -> putClientProperty("JTree.lineStyle", "Angled"); in the JTree constructor OR in the DefaultTreeCellRenderer constructor .. but it doesn't work :/
3) How to set a Java look and feel for my JTree (actually, I have a Windows look and feel ..)
I know .. I have grouped 3 question in the same topic ...
If anyone can help me on one of these subjects. .. Thanks !
Regards,
Didier

Answer 1

So, the Problem 1) is solved ..
About the Problem 2)
I put the code UIManager.setLookAndFeel(new javax.swing.plaf.metal.MetalLookAndFeel()) in the main method, like
  //Main method
  public static void main(String[] args) {
    try {
      UIManager.setLookAndFeel(new javax.swing.plaf.metal.MetalLookAndFeel());
    catch(Exception e) {
      e.printStackTrace();
    new MainApplication();
  }But it only set a Java L&F on the spliter, and on the toolbar contained in my application... Any idea why the title bar is not changed too ?
(The title bar stay with a Window$ XP L&F ...)
About the problem 3)
When I set the L&F->UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); then the lines appear .. ??!! .. if I set again the previous value UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); .. then the lines desappear ..