diff --git a/autoload/vimspector/internal/balloon.vim b/autoload/vimspector/internal/balloon.vim
index 4dc5096..b8be41a 100644
--- a/autoload/vimspector/internal/balloon.vim
+++ b/autoload/vimspector/internal/balloon.vim
@@ -138,7 +138,10 @@ function! s:MatchKey( key, candidates ) abort
   let mapped = ''
   for candidate in a:candidates
     try
-      " Try and expand the key code
+      " Try and expand the key code. Note this won't work for non-special keys
+      " and it won't work for multple keys, which is kinda shitty.
+      "
+      " There's no vim api to run expand_keycodes() i don't think.
       execute 'let mapped = "\' . candidate . '"'
       if mapped ==# a:key
         return v:true
diff --git a/python3/vimspector/settings.py b/python3/vimspector/settings.py
index e72bedf..9ad9e41 100644
--- a/python3/vimspector/settings.py
+++ b/python3/vimspector/settings.py
@@ -17,7 +17,6 @@
 import vim
 import builtins
 from vimspector import utils
-from collections.abc import Mapping
 
 DEFAULTS = {
   # UI
@@ -85,9 +84,7 @@ if hasattr( vim, 'Dictionary' ):
 
 def Dict( option ):
   return _UpdateDict( DICT_TYPE( DEFAULTS.get( option, {} ) ),
-                      utils.GetVimValue( vim.vars,
-                                         f'vimspector_{ option }',
-                                         {} ) )
+                      vim.vars.get( f'vimspector_{ option }', DICT_TYPE() ) )
 
 
 def _UpdateDict( target, override ):
@@ -118,9 +115,9 @@ def _UpdateDict( target, override ):
 
   for key, value in override.items():
     current_value = target.get( key )
-    if not isinstance( current_value, Mapping ):
+    if not isinstance( current_value, DICT_TYPE ):
       target[ key ] = value
-    elif isinstance( value, Mapping ):
+    elif isinstance( value, DICT_TYPE ):
       target[ key ] = _UpdateDict( current_value, value )
     else:
       target[ key ] = value
diff --git a/support/custom_ui_vimrc b/support/custom_ui_vimrc
index b1ffda1..3b132b4 100644
--- a/support/custom_ui_vimrc
+++ b/support/custom_ui_vimrc
@@ -142,4 +142,15 @@ augroup END
 
 " }}}
 
+" Custom mappings for special buffers {{{
+
+let g:vimspector_mappings = {
+      \   'stack_trace': {},
+      \   'variables': {
+      \    'set_value': [ '<Tab>', '<C-CR>' ],
+      \   },
+      \ }
+
+" }}}
+
 " vim: foldmethod=marker