I installed Debian 11/bullseye recently, and I noticed the buttons of the “Save” dialog box are at the upper side of the window. It looked strange.
How to solve this problem?
Method 1. Through the Xfce4 Settings Editor
Open the Xfce4 Setting Editor (in the main menu: Applications/Settings/Settings Editor):
In the Xsettings channel, path Gtk, uncheck the Value of the DialogsUseHeader property. (i.e., Set the DialogsUseHeader to False).
Method 2. Command line
xfconf-query -c xsettings -p /Gtk/DialogsUseHeader -s false
Now the problem has been fixed.