Resize handles in fluxbox
You will find the resize handles appear whenever your mouse clicks on a frame element such as the top bar or if you hit the small side or bottom bars. Each style is different, but I like to use the Rancor style and for me the resize handles are 3-4 pixels wide and colored in silver on the red frame. All the minimize/maximize/close and other window features also appear when you click on the frame.
The older version of fluxbox had an ugly little tag that hung off the side of the window and was usually too small for the text. The new version is a big improvement in my books.
KS