[Keyboard Manager] Add "alone" (tap) condition for single-key remaps (dual-key / to_if_alone) by MasaYan24 · Pull Request #49136 · microsoft/PowerToys

MasaYan24 · 2026-07-05T02:13:36Z

Summary of the Pull Request

Adds an optional "alone" condition to single-key remaps in Keyboard Manager, bringing
Karabiner-style to_if_alone (dual-key / tap-vs-hold) behavior: a key can perform one action
when tapped by itself while still acting as its normal self when combined with other keys.

Example use case: Right Ctrl → IME On when tapped alone, Left Ctrl → IME Off when tapped alone,
while Right/Left Ctrl + other keys keep working as normal Ctrl-based shortcuts. This is the
Windows equivalent of the popular macOS "left/right ⌘ → 英数/かな" mapping.

PR Checklist

Closes: Keyboard Manager: Add support for single-key press detection, IME switching, and flexible remapping with modifier combinations #40647
Related: [KBM] Separate function for key press vs key hold (a la dual-key-remap) #5679 (broader dual-key / to_if_alone tracking issue; Keyboard Manager: Add support for single-key press detection, IME switching, and flexible remapping with modifier combinations #40647 was closed as a duplicate of it)
Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
Tests: Added/updated and all pass
Localization: All end-user-facing strings can be localized
Dev docs: Added/updated
New binaries: Added on the required places — N/A: no new binaries/projects are introduced (existing engine, editor UI and test projects only).
Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Engine (C++):

New separate remap table aloneSingleKeyReMap (parallel to singleKeyReMap) with
Add/Clear/GetSingleKeyAloneRemap (MappingConfiguration).
New handler HandleSingleKeyAloneRemapEvent using a lazy + release-fire strategy:
suppress the alone key's key-down; on the first other key it flushes the original key-down
(promoting to a normal combination); on solo release it fires the alone action. Wired into the
hook dispatch before the normal single-key handler; per-key runtime state lives in State.
Settings JSON: an optional "condition" field per single-key remap ("always" default, or
"alone"). Fully backward compatible; both load and save handle it, so hand-edited or
UI-created alone remaps round-trip without loss.

Editor UI (WinUI3):

Native wrapper exposes parallel alone add/get/delete over the alone table (reuses the existing
SingleKeyMapping marshaling struct).
SingleKeyRemapCondition (Always / Alone) flows through the C# interop/service/model layers.
A localized "Condition" combo box in the add/edit dialog, shown only for a single-key
remap whose action is a key/shortcut (the case the engine supports), plus a localized
"Alone" badge on such rows in the list.

Known limitations / follow-ups (intentionally not in this PR):

Hold-timeout not implemented (holding the alone key then releasing still fires the alone action;
needs an injectable clock — deferred, noted in code).
Alone target supports a single key or a shortcut (not text/URL/app).

Validation Steps Performed

Engine unit tests: 108/108 (incl. 5 new alone tests + edge cases). Editor C++ tests: 88/88.
Editor UI project compiles clean (0 warnings / 0 errors).
Manual E2E on real hardware (self-built x64/Debug):
- Right Ctrl tapped alone → IME On; Left Ctrl tapped alone → IME Off (directional, idempotent).
- Ctrl+C / V / Z / A and existing Ctrl-based custom shortcuts unaffected (modifier pass-through OK).
- Editor UI: opening an existing alone remap shows Condition = "Alone (tap)"; saving round-trips a
  full real-world config (single-key + 70 global + 16 app-specific shortcuts) with zero loss;
  the "Alone" badge and the show/hide gating of the Condition combo both behave correctly.

…y tap/hold) Add a dual-key remap capability to the KBM engine: a single key can carry an "Alone" action that applies only when the key is tapped alone, while using it in combination with other keys passes the original key through as a real key/modifier (equivalent to Karabiner's to_if_alone). Uses the lazy + release-fire approach so the combination path has zero added latency. - New aloneSingleKeyReMap table plus Add/Clear/GetSingleKeyAloneRemap on MappingConfiguration/State, kept separate from the existing singleKeyReMap. - HandleSingleKeyAloneRemapEvent: suppresses the physical key-down (lazy); on another key-down it injects the original key as a real modifier (combination); on release with no intervening key it injects the alone action as a tap. - Per-key runtime state (pending vs combination) tracked in State across the separate key-down/key-up hook invocations. - 3 unit tests: no-injection-on-keydown, tap-alone injection, combination pass-through. Timeout-based cancellation (holding too long is not a tap) is intentionally deferred; it needs an injectable clock to be unit-testable. The handler is not yet wired into the runtime dispatch chain. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…ition" from settings - Call HandleSingleKeyAloneRemapEvent before HandleSingleKeyRemapEvent in the keyboard hook dispatch so alone-mapped keys are handled with priority (lazy key-down hold, tap-vs-combination decision). - Include aloneSingleKeyReMap in HasRegisteredRemappingsUnchecked so a config with only alone remaps still activates the engine. - Load an optional "condition" field on single-key remaps: "alone" routes the entry to the alone table; a missing field (or "always") keeps the legacy unconditional behavior, so existing settings files load unchanged. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…andler - Add unit tests for a disabled alone target (tapping injects nothing) and for a solo tap after a prior combination cycle (per-key runtime state resets cleanly). - Document HandleSingleKeyAloneRemapEvent and the optional "condition" settings field in the keyboard event handlers devdoc. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

SaveSettingsToFile previously wrote only singleKeyReMap and never persisted the aloneSingleKeyReMap table, so an alone remap loaded from settings was silently dropped the next time settings were saved. Add a serialization loop over aloneSingleKeyReMap that appends each entry to the inProcess array tagged with condition="alone", round-tripping with the (already condition-aware) loader. Regular remaps still omit the field and load as "always", so existing settings files are unchanged. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…dition Wire the "Alone" single-key remap condition through the WinUI3 editor so it can be created, edited, saved and reloaded. Previously the engine understood the condition and round-tripped it in settings, but the editor had no way to set or show it. - Native wrapper: parallel GetSingleKeyAloneRemapCount / GetSingleKeyAloneRemap / AddSingleKeyAloneRemap / AddSingleKeyAloneToShortcutRemap / DeleteSingleKeyAloneRemap over the aloneSingleKeyReMap table (reuses the existing SingleKeyMapping struct, so no marshaling changes). - C# interop/service: expose the alone add/get/delete and tag read-back mappings with IsAlone. - Model: SingleKeyRemapCondition (Always/Alone) on Remapping and ShortcutKeyMapping (including Equals/GetHashCode); settings correlation carries it. - UI: a Condition combo box on the mapping dialog; save/load/delete route to the alone table when the condition is Alone. Localizing the combo box (x:Uid/resw) and gating its visibility to single-key remaps are follow-ups. Engine (108) and editor (88) C++ unit test suites pass; the editor UI project compiles. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…dition

Polish the "Condition" (Always / Alone) control added for single-key dual-key remaps so it is production-ready: - Localize the combo box: replace the hardcoded "Condition" / "Always" / "Alone (tap)" strings with x:Uid + resw entries (ConditionComboBox.Header, Condition_Always.Content, Condition_Alone.Content), matching the existing ElevationComboBox pattern. - Gate visibility: the condition combo now shows only for a single-key remap whose action is a key/shortcut (the only case the engine supports "alone"), via UpdateConditionVisibility() driven off the trigger key count and action type. It starts collapsed and only toggles Visibility, so a condition set on load via SetCondition is preserved. - Surface the condition in the list: add an "Alone" badge (localized AloneBadge.Text) to the single-key remap rows, bound to a new Remapping.IsAlone via BoolToVisibilityConverter, so alone remaps are distinguishable without opening the edit dialog. Editor UI project compiles clean (0 warnings, 0 errors). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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Copilot

Pull request overview

This PR adds “tap-alone” (Karabiner-style to_if_alone) behavior for single-key remaps in Keyboard Manager, allowing a key to trigger an alternate action when tapped by itself while still behaving normally when used in combinations.

Changes:

Engine: adds a separate aloneSingleKeyReMap table and a new hook handler HandleSingleKeyAloneRemapEvent that defers decision until another key is pressed or the key is released.
Settings + interop: adds a "condition" field (always/alone) for single-key remaps and exposes parallel get/add/delete APIs for the alone table.
Editor UI: adds a localized “Condition” combo box (Always / Alone) and an “Alone” badge in the remap list.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/modules/keyboardmanager/KeyboardManagerEngineTest/TestHelpers.cpp	Resets alone-remap state between tests.
src/modules/keyboardmanager/KeyboardManagerEngineTest/SingleKeyRemappingTests.cpp	Adds unit tests covering basic alone key behavior.
src/modules/keyboardmanager/KeyboardManagerEngineLibrary/State.h	Adds runtime tracking for pending vs combination alone keys + API surface.
src/modules/keyboardmanager/KeyboardManagerEngineLibrary/State.cpp	Implements alone runtime state helpers and alone remap lookup.
src/modules/keyboardmanager/KeyboardManagerEngineLibrary/KeyboardManager.cpp	Wires alone handler into the hook chain and includes alone table in “has remaps”.
src/modules/keyboardmanager/KeyboardManagerEngineLibrary/KeyboardEventHandlers.h	Declares `HandleSingleKeyAloneRemapEvent`.
src/modules/keyboardmanager/KeyboardManagerEngineLibrary/KeyboardEventHandlers.cpp	Implements alone remap hook logic (lazy key-down, release-fire).
src/modules/keyboardmanager/KeyboardManagerEditorUI/Strings/en-US/Resources.resw	Adds localized strings for Condition UI and Alone badge.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Settings/SettingsManager.cs	Maps service-layer “IsAlone” into editor “Condition”.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Pages/MainPage.xaml.cs	Loads/saves remap condition and passes it into SaveMapping.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Pages/MainPage.xaml	Adds Alone badge to remap list UI.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Interop/ShortcutKeyMapping.cs	Introduces `SingleKeyRemapCondition` + includes it in equality/hash.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Interop/KeyMapping.cs	Tags service-returned mappings with `IsAlone`.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Interop/KeyboardMappingService.cs	Surfaces alone mappings and provides add/delete methods.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Interop/KeyboardManagerInterop.cs	Adds P/Invoke exports for alone remap APIs.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Helpers/RemappingHelper.cs	Saves/deletes single-key mappings using condition to choose table.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Helpers/Remapping.cs	Stores condition and computes `IsAlone` for list badge binding.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Controls/UnifiedMappingControl.xaml.cs	Adds condition getter/setter + visibility gating logic.
src/modules/keyboardmanager/KeyboardManagerEditorUI/Controls/UnifiedMappingControl.xaml	Adds Condition combo box to the mapping UI.
src/modules/keyboardmanager/KeyboardManagerEditorLibraryWrapper/KeyboardManagerEditorLibraryWrapper.h	Exposes alone remap APIs to the editor wrapper.
src/modules/keyboardmanager/KeyboardManagerEditorLibraryWrapper/KeyboardManagerEditorLibraryWrapper.cpp	Implements alone remap enumeration/add/delete in wrapper.
src/modules/keyboardmanager/common/MappingConfiguration.h	Adds alone remap table + APIs.
src/modules/keyboardmanager/common/MappingConfiguration.cpp	Loads/saves alone condition via optional `"condition"` field and serializes alone table.
src/modules/keyboardmanager/common/KeyboardManagerConstants.h	Adds `"condition"` setting constants (`always`/`alone`).
doc/devdocs/modules/keyboardmanager/keyboardeventhandlers.md	Documents the new alone handler behavior and settings format.

+                    // Tapped alone: fire the remapped alone action as a tap (down + up).
+                    std::vector<INPUT> keyEventList;
+                    const auto& target = it->second;
+                    if (target.index() == 0)
+                    {
+                        const DWORD targetKey = std::get<DWORD>(target);
+                        // A disabled alone target means "tapping alone does nothing".
+                        if (targetKey != CommonSharedConstants::VK_DISABLED)
+                        {
+                            Helpers::SetKeyEvent(keyEventList, INPUT_KEYBOARD, static_cast<WORD>(targetKey), 0, KeyboardManagerConstants::KEYBOARDMANAGER_SINGLEKEY_FLAG);
+                            Helpers::SetKeyEvent(keyEventList, INPUT_KEYBOARD, static_cast<WORD>(targetKey), KEYEVENTF_KEYUP, KeyboardManagerConstants::KEYBOARDMANAGER_SINGLEKEY_FLAG);
+                        }
+                    }
+                    // NOTE: Shortcut- and text-valued alone targets are a later phase (no producer yet).
+


+        // Step 1: a key-down of a DIFFERENT key while alone keys are pending means those pending keys
+        // are now being used in combination. Flush them by injecting their original key-down as a real
+        // key/modifier so the in-combination behavior (e.g. Right Ctrl acting as Ctrl) works.
+        if (isKeyDown)
+        {
+            for (const DWORD pendingKey : state.GetPendingAloneKeys())


+3. [HandleShortcutRemapEvent](#HandleShortcutRemapEvent)
 3. [HandleOSLevelShortcutRemapEvent](#HandleOSLevelShortcutRemapEvent)
 4. [HandleAppSpecificShortcutRemapEvent](#HandleAppSpecificShortcutRemapEvent)
 5. [HandleSingleKeyToggleToModEvent (Obsolete))](#HandleSingleKeyToggleToModEvent-(Obsolete---Code-from-PoC-which-is-commented-out))


MasaYan24 and others added 7 commits July 5, 2026 10:10

[Keyboard Manager] Update devdoc: editor UI now exposes the alone con…

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MasaYan24 mentioned this pull request Jul 5, 2026

[KBM] Separate function for key press vs key hold (a la dual-key-remap) #5679

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MasaYan24 marked this pull request as ready for review July 5, 2026 11:14

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[Keyboard Manager] Add "alone" (tap) condition for single-key remaps (dual-key / to_if_alone)#49136

[Keyboard Manager] Add "alone" (tap) condition for single-key remaps (dual-key / to_if_alone)#49136
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MasaYan24 commented Jul 5, 2026 •

edited

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MasaYan24 commented Jul 5, 2026 •

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