Example of setting terminal window size sensibly

support/custom_ui_vimrc

@@ -17,13 +17,37 @@ function! s:CustomiseUI()
   call win_gotoid( wins.stack_trace )
   wincmd r
 
+  " Make the left column at least 70 chars
+  70wincmd |
+
+  " Make the code window at least 80 chars
+  call win_gotoid( wins.code )
+  80wincmd |
+
   " Make the output window 10 lines high and right at the top of the screen
   call win_gotoid( wins.output )
   10wincmd _
   wincmd K
 endfunction
 
+function s:SetUpTerminal()
+  let terminal_win = g:vimspector_session_windows.terminal
+
+  " Make the terminal window at most 80 columns wide, ensuring there is enough
+  " sapce for our code window (80 columns) and the left bar (70 columns)
+
+  " Padding is 2 for the 2 vertical split markers and 2 for the sign column in
+  " the code window.
+  let left_bar = 70
+  let code = 80
+  let padding = 4
+  let cols = max( [ min([ &columns - left_bar - code - padding, 80 ] ), 10 ] )
+  call win_gotoid( terminal_win )
+  execute cols . 'wincmd |'
+endfunction
+
 augroup TestUICustomistaion
   autocmd!
   autocmd User VimspectorUICreated call s:CustomiseUI()
+  autocmd User VimspectorTerminalOpened call s:SetUpTerminal()
 augroup END