Minor feature request

Hello! First and foremost, thank you for creating this very handy plugin. If possible, I wanted to suggest a feature that would make using the plugin more efficient. After clicking on the icon for the custom CSS class and then selecting the desired one in the pop-up window, one must then click again on the X to close the pop-up window. For lengthy forms, it would be terrific if the latter step were not needed. In other words, the pop-up window would close automatically once the relevant CSS class was selected — no additional click required.

Thank for you considering this idea!