In the SignInWindow of the trial registry the login textfield has always a red border, because it executes the validation (must not empty) too earlier. So it is necessary to set the focus on that textfield, if we open the window. The following code is copied from the Sencha forum:

Window window = new Window();
window.setWidth(400);
FormPanel formPanel = new FormPanel();                 
                
TextField<String> passwordField = new TextField<String>();                
passwordField.setFieldLabel("xyz");
passwordField.setEmptyText("abcd");
passwordField.setAllowBlank(false);    
passwordField.setMaxLength(255);
passwordField.setPassword(true);
// passwordField.focus(); - Comment this
                
formPanel.add(passwordField);
window.add(formPanel);

window.setFocusWidget(passwordField); // Added this line
window.show();

It doesn’t work to set focus() on the textfield, it is better to let the window decide that.