diff --git a/nvimrc b/nvimrc
index 6eb66e3..6a7ae2e 100644
--- a/nvimrc
+++ b/nvimrc
@@ -266,6 +266,7 @@ runtime macros/matchit.vim
 
 " load other plugins:
 packadd! rust.vim          " https://github.com/rust-lang/rust.vim.git
+" TODO: replace with nvim_cmp:
 packadd! tmux-complete.vim " https://github.com/wellle/tmux-complete.vim.git
 packadd! vim-commentary    " https://github.com/tpope/vim-commentary.git
 packadd! vim-rails         " https://github.com/tpope/vim-rails.git
diff --git a/vim/lua/nvim_cmp_config.lua b/vim/lua/nvim_cmp_config.lua
index 3cb963c..bad5322 100644
--- a/vim/lua/nvim_cmp_config.lua
+++ b/vim/lua/nvim_cmp_config.lua
@@ -3,7 +3,7 @@ local cmp = require("cmp")
 
 cmp.setup({
 	completion = {
-		completeopt = "menu,menuone,noinsert,noselect",
+		completeopt = "menu,menuone,noselect",
 	},
 	snippet = {
 		expand = function(args)
@@ -18,10 +18,32 @@ cmp.setup({
 	mapping = cmp.mapping.preset.insert({
 		["<C-u>"] = cmp.mapping.scroll_docs(-4),
 		["<C-d>"] = cmp.mapping.scroll_docs(4),
-		["<C-Space>"] = cmp.mapping.complete(),
 		["<C-e>"] = cmp.mapping.close(),
 		["C-y"] = cmp.mapping.confirm({ select = true, behaviour = cmp.ConfirmBehavior.Replace }),
 		["<CR>"] = cmp.mapping.confirm({ select = true, behaviour = cmp.ConfirmBehavior.Replace }),
+		-- https://github.com/hrsh7th/nvim-cmp/wiki/Example-mappings#super-tab-like-mapping
+		["<C-Space>"] = cmp.mapping.confirm({
+			behavior = cmp.ConfirmBehavior.Insert,
+			select = true,
+		}),
+		["<Tab>"] = function(fallback)
+			if not cmp.select_next_item() then
+				if vim.bo.buftype ~= "prompt" and has_words_before() then
+					cmp.complete()
+				else
+					fallback()
+				end
+			end
+		end,
+		["<S-Tab>"] = function(fallback)
+			if not cmp.select_prev_item() then
+				if vim.bo.buftype ~= "prompt" and has_words_before() then
+					cmp.complete()
+				else
+					fallback()
+				end
+			end
+		end,
 	}),
 	sources = cmp.config.sources({
 		{ name = "copilot", keyword_length = 0 },
diff --git a/vim/lua/treesitter_config.lua b/vim/lua/treesitter_config.lua
index eabcb81..8d4ed4d 100644
--- a/vim/lua/treesitter_config.lua
+++ b/vim/lua/treesitter_config.lua
@@ -1,4 +1,5 @@
 require("nvim-treesitter.configs").setup({
+	-- TODO: only install needed
 	ensure_installed = "all",
 	highlight = {
 		enable = true,