GXT 3.0 branch, rev 2528. Also seen in 3.0.1. All browsers.

For both Window and Dialog widgets, if you setResizable(false) the mouse resize cursor styles are still shown when the widget is displayed. The user then expects to be able to resize the widget when they shouldn't be able to.

Si

Code:
Dialog dialog = new Dialog();
dialog.setHeadingText("Dialog");
dialog.setResizable(false);
dialog.add(new Label("Hello World"));
dialog.show();

Window window = new Window();
window.setHeadingText("Window");
window.setResizable(false);
window.add(new Label("Hello World"));