This adaptation of the OL ModifyFeature is completely independent of the layer styleMap and brings its default styles, these styles are conigurables.
Is obtained an improvement of usability by separating the tools and allowing a different icon for each tool.
Also allows a delete tool and add custom tools (eg to modify attributes: see points on this example, or close a line as a ring: see lines) And empowers to use <esc-key> to cancel the current drag.
View the modify-feature.js source to see how this is done.