Help to set up bspwm on Ubuntu in VMware

I've installed bspwm and sxhkd on Ubuntu Server LTS 24.04 in vmware. I use lightDM as display manager, qterminal as terminal emulator. When I open a terminal in bspwm gui, it looks like there are some kind of buffer: a letter I typed would not appear until I type again. (for example, when I type 'Hello', the 'e' wouldn't appear until I type 'l'), backspace and enter have the same problem. Other TTYs are alright. Any ideas why that happens? Thanks in advance.