diff --git a/src/alias_registry.cc b/src/alias_registry.cc
index 11d83ff0..9804aefc 100644
--- a/src/alias_registry.cc
+++ b/src/alias_registry.cc
@@ -12,7 +12,7 @@ void AliasRegistry::add_alias(String alias, String command)
     kak_assert(CommandManager::instance().command_defined(command));
     auto it = m_aliases.find(alias);
     if (it == m_aliases.end())
-        m_aliases.append({std::move(alias), std::move(command) });
+        m_aliases.insert({std::move(alias), std::move(command) });
     else
         it->value = std::move(command);
 }
diff --git a/src/alias_registry.hh b/src/alias_registry.hh
index f2022aeb..e9437ab0 100644
--- a/src/alias_registry.hh
+++ b/src/alias_registry.hh
@@ -3,7 +3,7 @@
 
 #include "safe_ptr.hh"
 #include "string.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 
 namespace Kakoune
 {
@@ -16,7 +16,7 @@ public:
     void remove_alias(StringView alias);
     StringView operator[](StringView name) const;
 
-    using AliasMap = IdMap<String, MemoryDomain::Aliases>;
+    using AliasMap = HashMap<String, String, MemoryDomain::Aliases>;
     using iterator = AliasMap::const_iterator;
 
     Vector<StringView> aliases_for(StringView command) const;
diff --git a/src/commands.cc b/src/commands.cc
index 943f843a..a84a0f41 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -663,7 +663,7 @@ Completions add_highlighter_completer(
     if (token_to_complete == 1 and params[0] == "-group")
         return complete_highlighter(context, params[1], pos_in_token, true);
     else if (token_to_complete == 0 or (token_to_complete == 2 and params[0] == "-group"))
-        return { 0_byte, arg.length(), complete(arg, pos_in_token, HighlighterRegistry::instance() | transform(HighlighterRegistry::get_id)) };
+        return { 0_byte, arg.length(), complete(arg, pos_in_token, HighlighterRegistry::instance() | transform(std::mem_fn(&HighlighterRegistry::Item::key))) };
     return Completions{};
 }
 
diff --git a/src/env_vars.cc b/src/env_vars.cc
index 0e5c53e8..8b293ff2 100644
--- a/src/env_vars.cc
+++ b/src/env_vars.cc
@@ -16,7 +16,7 @@ EnvVarMap get_env_vars()
         const char* value = name;
         while (*value != 0 and *value != '=')
             ++value;
-        env_vars.append({{name, value}, (*value == '=') ? value+1 : String{}});
+        env_vars.insert({{name, value}, (*value == '=') ? value+1 : String{}});
     }
     return env_vars;
 }
diff --git a/src/env_vars.hh b/src/env_vars.hh
index 7445c216..ed496d6c 100644
--- a/src/env_vars.hh
+++ b/src/env_vars.hh
@@ -1,13 +1,13 @@
 #ifndef env_vars_hh_INCLUDED
 #define env_vars_hh_INCLUDED
 
-#include "id_map.hh"
+#include "hash_map.hh"
 
 namespace Kakoune
 {
 
 class String;
-using EnvVarMap = IdMap<String, MemoryDomain::EnvVars>;
+using EnvVarMap = HashMap<String, String, MemoryDomain::EnvVars>;
 
 EnvVarMap get_env_vars();
 
diff --git a/src/hash_map.cc b/src/hash_map.cc
index 131dc615..4db90f8c 100644
--- a/src/hash_map.cc
+++ b/src/hash_map.cc
@@ -50,8 +50,8 @@ UnitTest test_hash_map{[] {
     {
         HashMap<String, int> map;
         map.insert({"test", 10});
-        kak_assert(map["test"_sv] == 10);
-        map.remove("test"_sv);
+        kak_assert(map[StringView{"test"}] == 10);
+        map.remove(StringView{"test"});
     }
 
     // make sure we get what we expect from the hash map
diff --git a/src/hash_map.hh b/src/hash_map.hh
index bbe9f1f9..df8fd306 100644
--- a/src/hash_map.hh
+++ b/src/hash_map.hh
@@ -160,11 +160,6 @@ struct HashMap
         HashCompatible<Key, typename std::decay<KeyType>::type>::value
     >::type;
 
-    // For IdMap inteface compatibility, to remove
-    using Element = Item;
-    Value& append(Item item) { return insert(std::move(item)); }
-    static const String& get_id(const Element& e) { return e.key; }
-
     template<typename KeyType, typename = EnableIfHashCompatible<KeyType>>
     int find_index(const KeyType& key, size_t hash) const
     {
diff --git a/src/highlighter.hh b/src/highlighter.hh
index 23f273a1..f8b020a4 100644
--- a/src/highlighter.hh
+++ b/src/highlighter.hh
@@ -5,7 +5,7 @@
 #include "completion.hh"
 #include "display_buffer.hh"
 #include "exception.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 #include "array_view.hh"
 #include "string.hh"
 #include "utils.hh"
@@ -71,7 +71,7 @@ struct HighlighterFactoryAndDocstring
     String docstring;
 };
 
-struct HighlighterRegistry : IdMap<HighlighterFactoryAndDocstring, MemoryDomain::Highlight>,
+struct HighlighterRegistry : HashMap<String, HighlighterFactoryAndDocstring, MemoryDomain::Highlight>,
                              Singleton<HighlighterRegistry>
 {};
 
diff --git a/src/highlighter_group.cc b/src/highlighter_group.cc
index 2d0a7a74..ebb28cf6 100644
--- a/src/highlighter_group.cc
+++ b/src/highlighter_group.cc
@@ -19,7 +19,7 @@ void HighlighterGroup::add_child(HighlighterAndId&& hl)
     if (m_highlighters.contains(hl.first))
         throw runtime_error(format("duplicate id: '{}'", hl.first));
 
-    m_highlighters.append({ std::move(hl.first), std::move(hl.second) });
+    m_highlighters.insert({std::move(hl.first), std::move(hl.second)});
 }
 
 void HighlighterGroup::remove_child(StringView id)
@@ -52,9 +52,9 @@ Completions HighlighterGroup::complete_child(StringView path, ByteCount cursor_p
 
     auto candidates = complete(
         path, cursor_pos,
-        m_highlighters | filter([=](const HighlighterMap::Element& hl)
+        m_highlighters | filter([=](const HighlighterMap::Item& hl)
                                 { return not group or hl.value->has_children(); })
-                       | transform(HighlighterMap::get_id));
+                       | transform(std::mem_fn(&HighlighterMap::Item::key)));
 
     return { 0, 0, std::move(candidates) };
 }
diff --git a/src/highlighter_group.hh b/src/highlighter_group.hh
index 7cd525a6..690e9514 100644
--- a/src/highlighter_group.hh
+++ b/src/highlighter_group.hh
@@ -2,7 +2,7 @@
 #define highlighter_group_hh_INCLUDED
 
 #include "exception.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 #include "highlighter.hh"
 #include "utils.hh"
 
@@ -28,7 +28,7 @@ public:
     Completions complete_child(StringView path, ByteCount cursor_pos, bool group) const override;
 
 private:
-    using HighlighterMap = IdMap<std::unique_ptr<Highlighter>, MemoryDomain::Highlight>;
+    using HighlighterMap = HashMap<String, std::unique_ptr<Highlighter>, MemoryDomain::Highlight>;
     HighlighterMap m_highlighters;
 };
 
diff --git a/src/highlighters.cc b/src/highlighters.cc
index fe16f6c3..f3cc1baa 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -1291,12 +1291,12 @@ public:
 
         for (auto& region : m_regions)
         {
-            m_groups.append({region.m_name, HighlighterGroup{}});
+            m_groups.insert({region.m_name, HighlighterGroup{}});
             if (region.m_begin.empty() or region.m_end.empty())
                 throw runtime_error("invalid regex for region highlighter");
         }
         if (not m_default_group.empty())
-            m_groups.append({m_default_group, HighlighterGroup{}});
+            m_groups.insert({m_default_group, HighlighterGroup{}});
     }
 
     void highlight(const Context& context, HighlightFlags flags, DisplayBuffer& display_buffer, BufferRange range) override
@@ -1371,7 +1371,7 @@ public:
             return offset_pos(hl.complete_child(path.substr(offset), cursor_pos - offset, group), offset);
         }
 
-        auto container = m_groups | transform(decltype(m_groups)::get_id);
+        auto container = m_groups | transform(std::mem_fn(&decltype(m_groups)::Item::key));
         return { 0, 0, complete(path, cursor_pos, container) };
     }
 
@@ -1411,7 +1411,7 @@ public:
 private:
     const RegionDescList m_regions;
     const String m_default_group;
-    IdMap<HighlighterGroup, MemoryDomain::Highlight> m_groups;
+    HashMap<String, HighlighterGroup, MemoryDomain::Highlight> m_groups;
 
     struct Region
     {
@@ -1521,66 +1521,66 @@ void register_highlighters()
 {
     HighlighterRegistry& registry = HighlighterRegistry::instance();
 
-    registry.append({
+    registry.insert({
         "number_lines",
         { number_lines_factory,
           "Display line numbers \n"
           "Parameters: -relative, -hlcursor, -separator <separator text>\n" } });
-    registry.append({
+    registry.insert({
         "show_matching",
         { create_matching_char_highlighter,
           "Apply the MatchingChar face to the char matching the one under the cursor" } });
-    registry.append({
+    registry.insert({
         "show_whitespaces",
         { show_whitespaces_factory,
           "Display whitespaces using symbols \n"
           "Parameters: -tab <separator> -tabpad <separator> -lf <separator> -spc <separator> -nbsp <separator>\n" } });
-    registry.append({
+    registry.insert({
         "fill",
         { create_fill_highlighter,
           "Fill the whole highlighted range with the given face" } });
-    registry.append({
+    registry.insert({
         "regex",
         { RegexHighlighter::create,
           "Parameters: <regex> <capture num>:<face> <capture num>:<face>...\n"
           "Highlights the matches for captures from the regex with the given faces" } });
-    registry.append({
+    registry.insert({
         "dynregex",
         { create_dynamic_regex_highlighter,
           "Parameters: <expr> <capture num>:<face> <capture num>:<face>...\n"
           "Evaluate expression at every redraw to gather a regex" } });
-    registry.append({
+    registry.insert({
         "group",
         { create_highlighter_group,
           "Parameters: <group name>\n"
           "Creates a named group that can contain other highlighters" } });
-    registry.append({
+    registry.insert({
         "flag_lines",
         { create_flag_lines_highlighter,
           "Parameters: <option name> <bg color>\n"
           "Display flags specified in the line-flag-list option <option name>\n"
           "A line-flag is written: <line>|<fg color>|<text>, the list is : separated" } });
-    registry.append({
+    registry.insert({
         "ranges",
         { create_ranges_highlighter,
           "Parameters: <option name>\n"
           "Use the range-faces option given as parameter to highlight buffer\n" } });
-    registry.append({
+    registry.insert({
         "line",
         { create_line_highlighter,
           "Parameters: <value string> <face>\n"
           "Highlight the line given by evaluating <value string> with <face>" } });
-    registry.append({
+    registry.insert({
         "column",
         { create_column_highlighter,
           "Parameters: <value string> <face>\n"
           "Highlight the column given by evaluating <value string> with <face>" } });
-    registry.append({
+    registry.insert({
         "ref",
         { create_reference_highlighter,
           "Parameters: <path>\n"
           "Reference the highlighter at <path> in shared highglighters" } });
-    registry.append({
+    registry.insert({
         "regions",
         { RegionsHighlighter::create,
           "Parameters: [-default <default group>] [-match-capture] <name> {<region name> <begin> <end> <recurse>}..."
diff --git a/src/hook_manager.cc b/src/hook_manager.cc
index ba3f2782..a5f2f7e0 100644
--- a/src/hook_manager.cc
+++ b/src/hook_manager.cc
@@ -14,7 +14,7 @@ namespace Kakoune
 void HookManager::add_hook(StringView hook_name, String group, HookFunc hook)
 {
     auto& hooks = m_hooks[hook_name];
-    hooks.append({std::move(group), std::move(hook)});
+    hooks.insert({std::move(group), std::move(hook)});
 }
 
 void HookManager::remove_hooks(StringView group)
@@ -30,7 +30,7 @@ CandidateList HookManager::complete_hook_group(StringView prefix, ByteCount pos_
     CandidateList res;
     for (auto& list : m_hooks)
     {
-        auto container = list.value | transform(decltype(list.value)::get_id);
+        auto container = list.value | transform(std::mem_fn(&decltype(list.value)::Item::key));
         for (auto& c : complete(prefix, pos_in_token, container))
         {
             if (!contains(res, c))
diff --git a/src/hook_manager.hh b/src/hook_manager.hh
index 6ce6d586..8198e079 100644
--- a/src/hook_manager.hh
+++ b/src/hook_manager.hh
@@ -1,7 +1,7 @@
 #ifndef hook_manager_hh_INCLUDED
 #define hook_manager_hh_INCLUDED
 
-#include "id_map.hh"
+#include "hash_map.hh"
 #include "completion.hh"
 #include "safe_ptr.hh"
 
@@ -29,7 +29,7 @@ private:
     friend class Scope;
 
     SafePtr<HookManager> m_parent;
-    IdMap<IdMap<HookFunc, MemoryDomain::Hooks>, MemoryDomain::Hooks> m_hooks;
+    HashMap<String, HashMap<String, HookFunc, MemoryDomain::Hooks>, MemoryDomain::Hooks> m_hooks;
     mutable Vector<std::pair<StringView, StringView>, MemoryDomain::Hooks> m_running_hooks;
 };
 
diff --git a/src/id_map.hh b/src/id_map.hh
deleted file mode 100644
index b297ea59..00000000
--- a/src/id_map.hh
+++ /dev/null
@@ -1,124 +0,0 @@
-#ifndef id_map_hh_INCLUDED
-#define id_map_hh_INCLUDED
-
-#include "string.hh"
-#include "vector.hh"
-
-#include <algorithm>
-
-namespace Kakoune
-{
-
-template<typename Value, MemoryDomain domain = MemoryDomain::Undefined>
-class IdMap
-{
-public:
-    struct Element
-    {
-        Element(String k, Value v)
-            : hash(hash_value(k)), key(std::move(k)), value(std::move(v)) {}
-
-        size_t hash;
-        String key;
-        Value value;
-
-        bool operator==(const Element& other) const
-        {
-            return hash == other.hash and key == other.key and value == other.value;
-        }
-    };
-
-    using container_type = Vector<Element, domain>;
-    using iterator = typename container_type::iterator;
-    using const_iterator = typename container_type::const_iterator;
-
-    IdMap() = default;
-
-    IdMap(std::initializer_list<Element> val) : m_content{val} {}
-
-    void append(const Element& value)
-    {
-        m_content.push_back(value);
-    }
-
-    void append(Element&& value)
-    {
-        m_content.push_back(std::move(value));
-    }
-
-    iterator find(StringView id)
-    {
-        const size_t hash = hash_value(id);
-        return std::find_if(begin(), end(),
-                            [id, hash](const Element& e)
-                            { return e.hash == hash and e.key == id; });
-    }
-
-    const_iterator find(StringView id) const
-    {
-        return const_cast<IdMap*>(this)->find(id);
-    }
-
-    bool contains(StringView id) const
-    {
-        return find(id) != end();
-    }
-
-    void remove(StringView id)
-    {
-        auto it = find(id);
-        if (it != end())
-            m_content.erase(it);
-    }
-
-    void remove_all(StringView id)
-    {
-        const size_t hash = hash_value(id);
-        auto it = std::remove_if(begin(), end(), [id, hash](const Element& e)
-                                 { return e.hash == hash and e.key == id; });
-        m_content.erase(it, end());
-    }
-
-    Value& operator[](StringView id)
-    {
-        auto it = find(id);
-        if (it != m_content.end())
-            return it->value;
-
-        append({ id.str(), Value{} });
-        return (m_content.end()-1)->value;
-    }
-
-    template<MemoryDomain dom>
-    bool operator==(const IdMap<Value, dom>& other) const
-    {
-        return size() == other.size() and std::equal(begin(), end(), other.begin());
-    }
-
-    template<MemoryDomain dom>
-    bool operator!=(const IdMap<Value, dom>& other) const
-    {
-        return not (*this == other);
-    }
-
-    void reserve(size_t size) { m_content.reserve(size); }
-    size_t size() const { return m_content.size(); }
-    void clear() { m_content.clear(); }
-    void erase(iterator it) { m_content.erase(it); }
-
-    static const String& get_id(const Element& e) { return e.key; }
-
-    bool empty() const { return m_content.empty(); }
-
-    iterator       begin()       { return m_content.begin(); }
-    iterator       end()         { return m_content.end(); }
-    const_iterator begin() const { return m_content.begin(); }
-    const_iterator end()   const { return m_content.end(); }
-
-private:
-    container_type m_content;
-};
-
-}
-
-#endif // id_map_hh_INCLUDED
diff --git a/src/json_ui.cc b/src/json_ui.cc
index 1dada266..8a436513 100644
--- a/src/json_ui.cc
+++ b/src/json_ui.cc
@@ -230,7 +230,7 @@ void JsonUI::set_on_key(OnKeyCallback callback)
 }
 
 using JsonArray = Vector<Value>;
-using JsonObject = IdMap<Value>;
+using JsonObject = HashMap<String, Value>;
 
 static bool is_digit(char c) { return c >= '0' and c <= '9'; }
 
@@ -324,7 +324,7 @@ parse_json(const char* pos, const char* end)
             std::tie(element, pos) = parse_json(pos, end);
             if (not element)
                 return {};
-            object.append({ std::move(name), std::move(element) });
+            object.insert({ std::move(name), std::move(element) });
             if (not skip_while(pos, end, is_blank))
                 return {};
 
diff --git a/src/json_ui.hh b/src/json_ui.hh
index 6ced3ec4..1b35538f 100644
--- a/src/json_ui.hh
+++ b/src/json_ui.hh
@@ -4,6 +4,7 @@
 #include "user_interface.hh"
 #include "event_manager.hh"
 #include "coord.hh"
+#include "string.hh"
 
 namespace Kakoune
 {
diff --git a/src/ncurses_ui.hh b/src/ncurses_ui.hh
index 521d8020..02270a8d 100644
--- a/src/ncurses_ui.hh
+++ b/src/ncurses_ui.hh
@@ -1,12 +1,14 @@
 #ifndef ncurses_hh_INCLUDED
 #define ncurses_hh_INCLUDED
 
+#include "array_view.hh"
 #include "coord.hh"
 #include "event_manager.hh"
 #include "face.hh"
-#include "user_interface.hh"
-#include "array_view.hh"
 #include "hash_map.hh"
+#include "optional.hh"
+#include "string.hh"
+#include "user_interface.hh"
 
 namespace Kakoune
 {
diff --git a/src/option_types.hh b/src/option_types.hh
index 3d9548f9..d9dc7db7 100644
--- a/src/option_types.hh
+++ b/src/option_types.hh
@@ -6,7 +6,6 @@
 #include "units.hh"
 #include "coord.hh"
 #include "array_view.hh"
-#include "id_map.hh"
 #include "hash_map.hh"
 #include "flags.hh"
 #include "enum.hh"
@@ -107,44 +106,6 @@ struct option_type_name<Vector<T, D>>
     static String name() { return option_type_name<T>::name() + StringView{"-list"}; }
 };
 
-template<typename Value, MemoryDomain domain>
-String option_to_string(const IdMap<Value, domain>& opt)
-{
-    String res;
-    for (auto it = begin(opt); it != end(opt); ++it)
-    {
-        if (it != begin(opt))
-            res += list_separator;
-        String elem = escape(option_to_string(it->key), '=', '\\') + "=" +
-                      escape(option_to_string(it->value), '=', '\\');
-        res += escape(elem, list_separator, '\\');
-    }
-    return res;
-}
-
-template<typename Value, MemoryDomain domain>
-void option_from_string(StringView str, IdMap<Value, domain>& opt)
-{
-    opt.clear();
-    for (auto& elem : split(str, list_separator, '\\'))
-    {
-        Vector<String> pair_str = split(elem, '=', '\\');
-        if (pair_str.size() != 2)
-            throw runtime_error("map option expects key=value");
-        String key;
-        Value value;
-        option_from_string(pair_str[0], key);
-        option_from_string(pair_str[1], value);
-        opt.append({ std::move(key), std::move(value) });
-    }
-}
-
-template<typename T, MemoryDomain D>
-struct option_type_name<IdMap<T, D>>
-{
-    static String name() { return format("str-to-{}-map", option_type_name<T>::name()); }
-};
-
 template<typename Key, typename Value, MemoryDomain domain>
 String option_to_string(const HashMap<Key, Value, domain>& opt)
 {
diff --git a/src/parameters_parser.hh b/src/parameters_parser.hh
index 79f4f702..f45c0410 100644
--- a/src/parameters_parser.hh
+++ b/src/parameters_parser.hh
@@ -2,7 +2,7 @@
 #define parameters_parser_hh_INCLUDED
 
 #include "exception.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 #include "array_view.hh"
 #include "flags.hh"
 #include "optional.hh"
@@ -41,7 +41,7 @@ struct SwitchDesc
     String description;
 };
 
-using SwitchMap = IdMap<SwitchDesc, MemoryDomain::Commands>;
+using SwitchMap = HashMap<String, SwitchDesc, MemoryDomain::Commands>;
 
 String generate_switches_doc(const SwitchMap& opts);
 
diff --git a/src/register_manager.cc b/src/register_manager.cc
index d2133e95..ff8cd1ba 100644
--- a/src/register_manager.cc
+++ b/src/register_manager.cc
@@ -1,7 +1,7 @@
 #include "register_manager.hh"
 
 #include "assert.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 
 namespace Kakoune
 {
@@ -11,7 +11,7 @@ Register& RegisterManager::operator[](StringView reg) const
     if (reg.length() == 1)
         return (*this)[reg[0_byte]];
 
-    static const IdMap<Codepoint> reg_names = {
+    static const HashMap<String, Codepoint> reg_names = {
         { "slash", '/' },
         { "dquote", '"' },
         { "pipe", '|' },
diff --git a/src/remote.cc b/src/remote.cc
index 6a436d5c..4f9a9ca5 100644
--- a/src/remote.cc
+++ b/src/remote.cc
@@ -7,7 +7,7 @@
 #include "display_buffer.hh"
 #include "event_manager.hh"
 #include "file.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 #include "optional.hh"
 #include "user_interface.hh"
 
@@ -92,8 +92,8 @@ public:
         write(ConstArrayView<T>(vec));
     }
 
-    template<typename Val, MemoryDomain domain>
-    void write(const IdMap<Val, domain>& map)
+    template<typename Key, typename Val, MemoryDomain domain>
+    void write(const HashMap<Key, Val, domain>& map)
     {
         write<uint32_t>(map.size());
         for (auto& val : map)
@@ -213,17 +213,17 @@ public:
         return res;
     }
 
-    template<typename Val, MemoryDomain domain>
-    IdMap<Val, domain> read_idmap()
+    template<typename Key, typename Val, MemoryDomain domain>
+    HashMap<Key, Val, domain> read_hash_map()
     {
         uint32_t size = read<uint32_t>();
-        IdMap<Val, domain> res;
+        HashMap<Key, Val, domain> res;
         res.reserve(size);
         while (size--)
         {
-            auto key = read<String>();
+            auto key = read<Key>();
             auto val = read<Val>();
-            res.append({std::move(key), std::move(val)});
+            res.insert({std::move(key), std::move(val)});
         }
         return res;
     }
@@ -615,7 +615,7 @@ RemoteClient::RemoteClient(StringView session, std::unique_ptr<UserInterface>&&
                 m_ui->refresh(reader.read<bool>());
                 break;
             case MessageType::SetOptions:
-                m_ui->set_ui_options(reader.read_idmap<String, MemoryDomain::Options>());
+                m_ui->set_ui_options(reader.read_hash_map<String, String, MemoryDomain::Options>());
                 break;
             default:
                 kak_assert(false);
@@ -673,7 +673,7 @@ private:
                 auto init_cmds = m_reader.read<String>();
                 auto init_coord = m_reader.read_optional<BufferCoord>();
                 auto dimensions = m_reader.read<DisplayCoord>();
-                auto env_vars = m_reader.read_idmap<String, MemoryDomain::EnvVars>();
+                auto env_vars = m_reader.read_hash_map<String, String, MemoryDomain::EnvVars>();
                 auto* ui = new RemoteUI{sock, dimensions};
                 if (auto* client = ClientManager::instance().create_client(
                                        std::unique_ptr<UserInterface>(ui),
diff --git a/src/user_interface.hh b/src/user_interface.hh
index a6a65885..b202f188 100644
--- a/src/user_interface.hh
+++ b/src/user_interface.hh
@@ -2,7 +2,7 @@
 #define user_interface_hh_INCLUDED
 
 #include "array_view.hh"
-#include "id_map.hh"
+#include "hash_map.hh"
 
 #include <functional>
 
@@ -66,7 +66,7 @@ public:
 
     virtual void set_on_key(OnKeyCallback callback) = 0;
 
-    using Options = IdMap<String, MemoryDomain::Options>;
+    using Options = HashMap<String, String, MemoryDomain::Options>;
     virtual void set_ui_options(const Options& options) = 0;
 };