The software may have crashed. You can force the software to close by pressing Ctrl + Alt + Del on the keyboard and opening ‘Task Manager’. Find FDCreative.ISpaces.UI.exe in the list of running programs and choose the option to force the program to quit.
Note By doing this you will lose any unsaved changes you might have made to your system so be sure to save regularly if editing/creating themes or making changes.
If the problem persists, please submit a support request by clicking the 'Submit Request' link at the top of this page.