Button inside a Dialog widget switches icon on hover

[Muhammad Lukman Nasaruddin]

This is due to styling scoping of line 406 of CSS:

.ui-dialog .ui-state-hover span { background-position: -16px -16px ; }

Should be changed to:

.ui-dialog .ui-dialog-titlebar-close.ui-state-hover span { background-position: -16px -16px ; }