I'm not sure whether I am right here. It is less a bug than an idea for inproving user-friendlyness. Two points: 1.) My idea 2.) Why I express this idea here 1.) My Idea: For getting to know the possibilities of a DE, one might want to play a bit with the settings. Sometimes one might even forget which changes were made. Coming from Windows, I very miss the possibilities to confirm or reject the changes with an apply-/ok-/cancel-button. ...instead of a single close-button. Sometimes, when looking through the possible choices (e.g., in a drop-down-menu), changes are made by accident (call me clumsy but people are like that). And if you do not know what the original configuration was, a cancel-button would be great help. Even 'Esc' does not get me out there safe. Also I think it is more logical/intuitive, when a change has to be explicitly activated when closing the settings-window. ...like an agreement by handshake after having a look around in the shop ; ) 2.) Why I express this idea here: First, I wrote it on http://community.linuxmint.com/idea/view/4948 but I was told, they have nothing to do with Xfce-development. On http://www.xfce.org/community I followed the link [german] "Fehlererfassungssystem – Probleme, Korrekturen oder Ideen, um Xfce zu verbessern, melden" (meaning in short: 'report problems or ideas to improve Xfce') and was directed to this place. In case this is still the wrong place: Where would you recommend me to go?
This is a design decision in Xfce: in general, settings-changes are applied instantly, so an "apply" button doesn't make sense. The idea is to make it easier for people to change a simple setting without having to click "apply" every time. There are some notable exceptions, e.g. where changing a settings-change might break your setup or more than one variable is taken into account for the change to happen (display dialog would be one example). Anyway, bottom line is that this behavior won't be changed.