Bug 14668

Comment 1 Mike Wilson 2002-04-25 15:15:38 EDT

I have never understood how this code works. Last time I checked, it was 
working properly, but non-intuitively. SN to either fix the bug, or explain 
why it should be working the way it is.

Comment 2 Steve Northover 2002-04-26 14:49:58 EDT

Fixed > 20020426

Comment 3 Eduardo Pereira 2002-05-13 18:20:59 EDT

Tested build 0508 and the problem is still happening.

Comment 4 Steve Northover 2002-05-14 10:39:48 EDT

We put in code that attempted to fix the first problem by assigning focus to 
the default button if no focus was assigned by the programmer.  Not only did 
this break Eclipse, it was a dumb thing to do.  Setting focus to the button was 
useless because the user can hit return to activate the button.  Setting the 
focus to a single line text field in the same window for example would be more 
useful.

I can now see that setting focus to the default button when no focus is 
assigned only makes sense in the case that you have (ie. there are no widgets, 
other than buttons in the window).  This case seems too specific for SWT to 
code and ensure on all platforms.

I suggest that you set both the focus and the default button.  This should work 
fine.

Comment 5 Tod Creasey 2002-09-26 13:04:18 EDT

The problem is actually with not having a focus widget now (20020925).

If you instead run the code below you will see that the default button is 
correct because we have set focus on a different widget. If we use Eduardos 
example it will not work as focus was arbitrarily set to the first child of 
the shell - the first button.

This is an issue for us in the MessageDialog (which only has labels) as it 
prevents developers from setting default buttons.

import org.eclipse.swt.widgets.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Point;

public class DefaultButtonTest {

public static void main(String args[]) {
	
	Shell shell = new Shell();
	Display display = shell.getDisplay();
	Text label = new Text(shell, SWT.BORDER);
	label.setText("line 1\nline2\nline3\n\nline5");
	Point size = label.computeSize(SWT.DEFAULT,SWT.DEFAULT);
	shell.setBounds(100,100,200,200);
	label.setBounds(10,10,size.x,size.y);
	label.setFocus();
 	
	for (int i = 0; i < 3; i++) {
		Button b = new Button(shell,SWT.NULL);
		b.setBounds(20 + (i * 50),120,50,25);
		b.setText("B::" + i);
		if(i==1) {
			shell.setDefaultButton(b);
			System.out.println("Default should be: " + b.getText
()); 
		}
	}
	
	shell.open(); 

	while (!shell.isDisposed()) {
		if (!display.readAndDispatch())
			display.sleep();
	}
}
}

Comment 6 Steve Northover 2002-09-26 14:16:11 EDT

Because default button look is assigned to the focus widget on most platforms, 
when we assign focus to the first widget in the tree that takes focus and this 
widget is a button, the defualt look is removed from the button that was 
assigned by the application.  This is what is happening.

In order to fix this, SWT would need to traverse the widget tree to determine 
that there are no widgets other than buttons that will take focus (ie. the 
window is made up of labels and buttons), detect the fact that a default button 
has been set, and set focus to that button, instead of the first widget (a 
button) that will take focus.

Agreed with TC that JFace should set the focus to the default button in this 
case.

Comment 7 Tod Creasey 2002-09-26 15:14:17 EDT

Would it be possible for the Shell to remember if setDefaultButton() was 
called and then use the result of that to choose the focus widget if it is 
going to make a random choice later?

Comment 8 Steve Northover 2002-09-26 17:17:42 EDT

Nope, that was the original "fix" and Eclipse relies on setting focus to the 
first widget when no focus is explicitly set.  We once did this and ripped the 
code out, real fast.