Description Patrick Dubroy 2001-11-29 10:44:54 EST

public class DropDownTest {
public static void main(String[] argv) {
	Display display = new Display();
	Shell shell = new Shell(display);
	ToolBar toolBar = new ToolBar(shell, SWT.FLAT);
	ToolItem toolItem = new ToolItem(toolBar, SWT.DROP_DOWN);
	toolItem.addListener(SWT.Selection, new Listener() {
		public void handleEvent(Event e) {
			System.out.println("event occurred");	
		}
	});
	toolBar.setBounds(0, 0, 100, 50);
	Combo combo = new Combo(shell, SWT.DROP_DOWN);
	combo.add("foo");
	combo.setBounds(100, 0, 100, 25);
	shell.open();
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch()) display.sleep();	
	}
}
}
--
When this code is run on Windows, the following will happen:
1. If the mouse is pressed over the main part of the button (ie. not the arrow) 
the event is not sent until the button is released, just like a normal button.
2. If the mouse is pressed over the arrow, the event is sent as soon as the 
button is pressed, and before it is released.
This behaviour is consistent with the way combo boxes work on both Windows and 
Motif. ie., items can be selected from the dropdown as [button down] -> [move 
over desired item] -> [release button].

When the same code is run on Motif, the selection is only sent after the button 
is released no matter where the click occurred, on the arrow or on the main 
part of the button. This behaviour is inconsistent with Windows but especially 
with the way drop-down menus work in Motif.
--
Also the combo box displays slightly weird behaviour on Motif: if you click and 
release very quickly, the menu stays up but if you click, hold, and release, 
the menu disappears quickly. This could be a Motif feature though.