Q:

Couldn't resize project sidebar is doom emacs

I'm using doom emacs.
I've enabled treemacs in ~/.doom.d/init.el

I couldn't resize the project sidebar. I have tried this mac OS and opensuse 15.1
I get message <left-fringe> <mouse-drag-1> is undefined. Do I miss any configuration?

A:

Either set treemacs-width explicitly by adding something like (setq treemacs-width 30) to ~/.doom.d/config.el
Otherwise press tw to toggle fixed-width mode in treemacs, then you can resize it.
Adding (setq treemacs--width-is-locked nil) to ~/.doom.d/config.el may work too

