Couldn't resize project sidebar is doom emacs

Question

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?

Answer 1

I had to add these lines to my doom config in order to allow resizing via mouse to work:

(setq treemacs-width 30)
(setq treemacs--width-is-locked nil)
(setq treemacs-width-is-initially-locked nil)

Answer 2

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