I am not sure the problem is that there is an empty selection target or the order of the different targets when a tool is closed because of another bus message.

Ex:

• Create an extraction in a folder
• The modification tool of the new extraction is opened => OK
• Remove this exttraction
• The parent  folder is selected => OK
• The modification tool is closed => OK
• A selection bus message is sent with an empty target, that hide the selection of the folder => KO : the buttons reacting to the selection of folder are deactivated (ex: the new button to create an extraction in the folder)