Unexposed, hard-coded CSS class names can break extensible functionality
From beta3 to beta4, the CheckBoxSelectionModel class was changed because the CheckBoxColumnBaseAppearance class was changed. Specifically, the CSS class name of the grid cell housing the checkbox changed from "x-grid3-row-checker" to "x-grid-row-checker."
This change broke our extension of CheckBoxSelectionModel which ignores row clicks and prevents the checkbox from being selected when anything other than the checkbox is clicked.
I didn't see a way to turn this behavior off programmatically, hence the extension. Our extension mimics functionality in the parent class, using the CSS class name of the Element that was the target of the event, to determine what Element was clicked. Since the class names were changed, this broke functionality.
Is there a reason the class name was not exposed as a public static final string - even with in the GXT code itself - so that other classes can use it?