Bug 4793 Canvas.scroll not working when source y around 65536 (1GIXDPD)
Run the code below and press a key. You will see one pixel line of cheese at the top or bottom depending on which sourceY is used. To make this more obvious divide height by 2. This works fine on NT. import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.*; import org.eclipse.swt.widgets.*; public class PR_1GIXDPD { static boolean scrolled = false; public static void main(String[] args) { final Shell shell = new Shell(); shell.addListener(SWT.KeyDown, new Listener() { public void handleEvent(Event e) { Rectangle clientArea = shell.getClientArea(); int height = clientArea.height; int sourceY = 65536 - (height - 3); // int sourceY = 65536 + (height - 1); // does not work if 65536 - (height - 2) < sourceY < 65536 + height shell.scroll(0, 0, 0, sourceY, clientArea.width, clientArea.height, true); scrolled = true; System.out.println(clientArea); } }); shell.addListener(SWT.Paint, new Listener() { public void handleEvent(Event event) { int lineHeight = 15; if (scrolled == false) { for (int i = 0; i < event.y + event.height; i += lineHeight) { event.gc.drawText("Line " + i, 0, i); } } } }); shell.open(); Display display = shell.getDisplay (); while (!shell.isDisposed ()) { if (!display.readAndDispatch ()) display.sleep (); } } } NOTES:
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/actions/SelectionConverter.java
public static boolean canOperateOn(JavaEditor editor) {
		if (editor == null)
			return false;
		return getInput(editor) != null;
		
	}
	
	/**
	 * Converts the text selection provided by the given editor into an array of
	 * Java elements. If the selection doesn't cover a Java element and the selection's
	 * length is greater than 0 the methods returns the editor's input element.
	 */
	public static IJavaElement[] codeResolveOrInput(JavaEditor editor) throws JavaModelException {
		IJavaElement input= getInput(editor);
		ITextSelection selection= (ITextSelection)editor.getSelectionProvider().getSelection();
		IJavaElement[] result= codeResolve(input, selection);
		if (result.length == 0) {
			result= new IJavaElement[] {input};
		}
		return result;
	}
	
	public static IJavaElement[] codeResolveOrInputHandled(JavaEditor editor, Shell shell, String title) {
		try {
			return codeResolveOrInput(editor);
		} catch(JavaModelException e) {
			ExceptionHandler.handle(e, shell, title, ActionMessages.getString("SelectionConverter.codeResolve_failed")); 
		}
		return null;
	}