old_contents: pageflow.ConfigurationEditorTabView.groups.define('general', function() {
    this.input('title', pageflow.TextInputView, {required: true});
    this.input('hide_title', pageflow.CheckBoxInputView);
    this.input('tagline', pageflow.TextInputView);
    this.input('subtitle', pageflow.TextInputView);
    this.input('text', pageflow.TextAreaInputView);
    this.input('text_position', pageflow.SelectInputView, {values: pageflow.Page.textPositions});
    this.input('gradient_opacity', pageflow.SliderInputView);
    this.input('invert', pageflow.CheckBoxInputView);
  });
new_contents: pageflow.ConfigurationEditorTabView.groups.define('general', function() {
    this.input('title', pageflow.TextInputView, {required: true, maxLength: 5000});
    this.input('hide_title', pageflow.CheckBoxInputView);
    this.input('tagline', pageflow.TextInputView, {maxLength: 5000});
    this.input('subtitle', pageflow.TextInputView, {maxLength: 5000});
    this.input('text', pageflow.TextAreaInputView);
    this.input('text_position', pageflow.SelectInputView, {values: pageflow.Page.textPositions});
    this.input('gradient_opacity', pageflow.SliderInputView);
    this.input('invert', pageflow.CheckBoxInputView);
  });
  
subject: Increase max length for page tagline, title and subtitles