The titlebar is a rectangle on top of the window, behind which you can drag windows using only the mouse (without using the mod key).
- move "dwm-titlebar-6-8.diff" file to the directory with dwm
- do
patch -p1 < dwm-titlebar-6-8.diff - check that the patch was completed correctly. If something goes wrong, edit the file manually.
- recompile the dwm