Running "xfce4-terminal --drop-down" and setting the terminal width to "100%" can leave a few pixels of the screen width not taken by the window. This can lead to annoyances: often when I wish to select some text in the terminal, I want to move the mouse pointer to the left and then drag it down, but that doesn't work; I have to carefully align the pointer against the first column (see also bug 10297).

(If you ask me, I'd make the width setting based on columns instead of percentage-of-screen; or get rid of it altogether and always use 100% of the screen width. But maybe other people have contrary preferences.)