Gap on bottom left of tmuxline

[proever]

Hi there, I'm just getting started with vim/tmux, so I'm not quite sure how to solve this, but my tmuxline seems to have a small gap on the bottom left between the name of the session and the first window. This gap isn't there on the right. I'm using the Dracula theme, and haven't made any changes to tmuxline that I'm aware of. I'm not sure if this is expected behavior or not. If it is, is there a way to change it?

It looks better if I focus the second window.

Here are my init.vim (neovim rc) and tmux.conf files:

" init.vim
set nocompatible              " be iMproved, required
filetype off                  " required

set clipboard=unnamedplus

" set the runtime path to include Vundle and initialize
set rtp+=~/.config/nvim/bundle/Vundle.vim
call vundle#begin()
" alternatively, pass a path where Vundle should install plugins
call vundle#begin('~/.config/nvim/bundle')

" let Vundle manage Vundle, required
Plugin 'VundleVim/Vundle.vim'

" The following are examples of different formats supported.
" Keep Plugin commands between vundle#begin/end.
" plugin on GitHub repo
Plugin 'tpope/vim-fugitive'
Plugin 'tpope/vim-rhubarb'
Plugin 'vim-airline/vim-airline'
Plugin 'vim-airline/vim-airline-themes'

Plugin 'edkolev/tmuxline.vim'
Plugin 'christoomey/vim-tmux-navigator'

Plugin 'tpope/vim-unimpaired'
Plugin 'tpope/vim-obsession'

Plugin 'scrooloose/nerdtree'
Plugin 'scrooloose/nerdcommenter'
Plugin 'airblade/vim-gitgutter'
Plugin 'scrooloose/syntastic'
Plugin 'tpope/vim-surround'
Plugin 'valloric/youcompleteme'

Plugin 'hashivim/vim-terraform'

Plugin 'tmux-plugins/vim-tmux'

" Colors
Plugin 'dracula/vim'

" All of your Plugins must be added before the following line
call vundle#end()            " required
filetype plugin indent on    " required
" To ignore plugin indent changes, instead use:
"filetype plugin on

syntax on
colorscheme dracula

set showmatch
set ignorecase
set hlsearch
set tabstop=4
set softtabstop=4
set expandtab
set shiftwidth=4
set autoindent
set number
set wildmode=longest,list

set splitbelow
set splitright

set laststatus=2

let g:terraform_fmt_on_save=1
let g:terraform_align=1
let g:terraform_remap_spacebar=1

nnoremap <C-J> <C-W><C-J>
nnoremap <C-K> <C-W><C-K>
nnoremap <C-L> <C-W><C-L>
nnoremap <C-H> <C-W><C-H>

map :s5 :source % \| AirlineRefresh \| nohlsearch

" vv to generate new vertical split
nnoremap <silent> vv <C-w>v

" syntastic
set statusline+=%#warningmsg#
set statusline+=%{SyntasticStatuslineFlag()}
set statusline+=%*

let g:syntastic_always_populate_loc_list = 1
let g:syntastic_auto_loc_list = 1
let g:syntastic_check_on_open = 1
let g:syntastic_check_on_wq = 0

autocmd StdinReadPre * let s:std_in=1
autocmd VimEnter * if argc() == 0 && !exists("s:std_in") | NERDTree | endif

let g:NERDTreeWinSize=40

" Add spaces after comment delimiters by default
let g:NERDSpaceDelims = 1

" Use compact syntax for prettified multi-line comments
let g:NERDCompactSexyComs = 1

" Allow commenting and inverting empty lines (useful when commenting a region)
let g:NERDCommentEmptyLines = 1

" Enable trimming of trailing whitespace when uncommenting
let g:NERDTrimTrailingWhitespace = 1

# .tmux.conf
# fix for pasting from system clipboard in nvim
set -g default-shell $SHELL
set -g default-command "reattach-to-user-namespace -l ${SHELL}"

# Use vim keybindings in copy mode
setw -g mode-keys vi

# Bind ']' to use pbpaste
bind ] run "reattach-to-user-namespace pbpaste | tmux load-buffer - && tmux paste-buffer"

# Start windows and panes at 1, not 0
set -g base-index 1
setw -g pane-base-index 1

# remap prefix from 'C-b' to 'C-a'
unbind C-b
set-option -g prefix C-a
bind-key C-a send-prefix

# split panes using | and -
bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"
unbind '"'
unbind %

# reload config file (change file location to your the tmux.conf you want to use)
unbind r
bind r source-file ~/.tmux.conf

# quick pane cycling
unbind ^A
bind ^A select-pane -t :.+

is_vim="ps -o state= -o comm= -t '#{pane_tty}' \
  | grep -iqE '^[^TXZ ]+ +(\\S+\\/)?g?(view|n?vim?x?)(diff)?$'"

is_fzf="ps -o state= -o comm= -t '#{pane_tty}' \
  | grep -iqE '^[^TXZ ]+ +(\\S+\\/)?fzf$'"

bind -n C-h run "($is_vim && tmux send-keys C-h) || \
                 tmux select-pane -L"

bind -n C-j run "($is_vim && tmux send-keys C-j)  || \
                 ($is_fzf && tmux send-keys C-j) || \
                 tmux select-pane -D"

bind -n C-k run "($is_vim && tmux send-keys C-k) || \
                 ($is_fzf && tmux send-keys C-k)  || \
                 tmux select-pane -U"

bind -n C-l run "($is_vim && tmux send-keys C-l) || \
                 tmux select-pane -R"

bind-key -n C-\ if-shell "$is_vim" "send-keys C-\\" "select-pane -l"

# List of plugins
set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-sensible'
set -g @plugin 'tmux-plugins/tmux-resurrect'
set -g @plugin 'tmux-plugins/tmux-continuum'
set -g @continuum-restore 'on'
set -g @plugin 'tmux-plugins/tmux-sessionist'

set -g @continuum-save-interval '5'

# for neovim
set -g @resurrect-strategy-nvim 'session'

source ~/.tmux/tmuxline/snapshot

# Initialize TMUX plugin manager (keep this line at the very bottom of tmux.conf)
run '~/.tmux/plugins/tpm/tpm'