Tested OS: Xubuntu 14.04–15.04; Xfce version: 4.12; xfwm4 version: 4.12.1-1ubuntu1; theme: Zukitwo; icon theme: Evolvere Blue Folders Dark fallback. Download as pdf here or here.
Update, 2015-05-20: As of Xfce 4.12, this solution works without the need for plugins. It also works out of the box in Xubuntu 15.04, but may not in older versions unless you’ve updated to Xfce 4.12.
I found a little quirk when I upgraded to Xubuntu 14.04: the titlebar no longer appeared when I maximised a window. Because I habitually exploit the titlebar, this was a cumbersome change (or bug). Fortunately, I found out how to reverse it quickly enough.
Initially, I thought the solution was obvious enough to go without a mention. A recent article by Andrew on WebUpd81, though, introduced the intriguing xfce4-windowck-plugin2 by Alessio Piccoli and Cédric Leporcq. It's a set of two plugins enabling you to place a maximised window's title in the panel, along with the window's buttons. If you install xfce4-windowck-plugin, you likely want to disable the titlebar to avoid redundancy. Andrew and xfce4-windowck-plugin's developers suggest installing the external program Maximus or a patch for xfwm43.
My solution is simpler and doesn't require you to download or install anything.
