diff --git a/macSKK/Assets.xcassets/icon-sougou.imageset/Contents.json b/macSKK/Assets.xcassets/icon-sougou.imageset/Contents.json
new file mode 100644
index 00000000..ab96cc9a
--- /dev/null
+++ b/macSKK/Assets.xcassets/icon-sougou.imageset/Contents.json
@@ -0,0 +1,18 @@
+{
+  "images" : [
+    {
+      "filename" : "icon-sougou.png",
+      "idiom" : "mac",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "icon-sougou@2x.png",
+      "idiom" : "mac",
+      "scale" : "2x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}
diff --git a/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou.png b/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou.png
new file mode 100644
index 00000000..4eb3f002
Binary files /dev/null and b/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou.png differ
diff --git a/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou@2x.png b/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou@2x.png
new file mode 100644
index 00000000..4baaec5d
Binary files /dev/null and b/macSKK/Assets.xcassets/icon-sougou.imageset/icon-sougou@2x.png differ
diff --git a/macSKK/StateMachine.swift b/macSKK/StateMachine.swift
index 0ca1a3bf..512438aa 100644
--- a/macSKK/StateMachine.swift
+++ b/macSKK/StateMachine.swift
@@ -129,6 +129,11 @@ class StateMachine {
             }
             return true
         case .tab:
+            if case .register(let registerState) = state.specialState {
+                state.inputMethod = .composing(registerState.prev.composing)
+                updateMarkedText()
+                return true
+            }
             return false
         case .stickyShift:
             switch state.inputMode {
diff --git a/macSKKTests/StateMachineTests.swift b/macSKKTests/StateMachineTests.swift
index 24d5ce30..0b81190b 100644
--- a/macSKKTests/StateMachineTests.swift
+++ b/macSKKTests/StateMachineTests.swift
@@ -1531,6 +1531,38 @@ final class StateMachineTests: XCTestCase {
         wait(for: [expectation], timeout: 1.0)
     }
 
+    func testHandleRegisteringTab() {
+        let expectation = XCTestExpectation()
+        stateMachine.inputMethodEvent.collect(12).sink { events in
+            XCTAssertEqual(events[0], .markedText(MarkedText([.markerCompose, .plain("あ")])))
+            XCTAssertEqual(events[1], .markedText(MarkedText([.markerCompose, .plain("あい")])))
+            XCTAssertEqual(events[2], .modeChanged(.hiragana, .zero))
+            XCTAssertEqual(events[3], .markedText(MarkedText([.plain("[登録：あい]")])))
+            // 単語登録で空文字列のときにTabキーを押すと単語登録までの読みが補完される
+            XCTAssertEqual(events[4], .markedText(MarkedText([.plain("[登録：あい]"), .markerCompose, .plain("あい")])))
+            XCTAssertEqual(events[5], .markedText(MarkedText([.plain("[登録：あい]"), .markerCompose, .plain("あ")])))
+            XCTAssertEqual(events[6], .markedText(MarkedText([.plain("[登録：あい]")])))
+            XCTAssertEqual(events[7], .markedText(MarkedText([.markerCompose, .plain("あい")])))
+            XCTAssertEqual(events[8], .markedText(MarkedText([.markerCompose, .plain("あい*k")])))
+            XCTAssertEqual(events[9], .modeChanged(.hiragana, .zero))
+            XCTAssertEqual(events[10], .markedText(MarkedText([.plain("[登録：あい*く]")])))
+            XCTAssertEqual(events[11], .markedText(MarkedText([.plain("[登録：あい*く]"), .markerCompose, .plain("あい*く")])))
+            expectation.fulfill()
+        }.store(in: &cancellables)
+        XCTAssertTrue(stateMachine.handle(printableKeyEventAction(character: "a", withShift: true)))
+        XCTAssertTrue(stateMachine.handle(printableKeyEventAction(character: "i")))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .space, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .tab, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .tab, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .backspace, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .cancel, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .cancel, originalEvent: nil, cursorPosition: .zero)))
+        XCTAssertTrue(stateMachine.handle(printableKeyEventAction(character: "k", withShift: true)))
+        XCTAssertTrue(stateMachine.handle(printableKeyEventAction(character: "u")))
+        XCTAssertTrue(stateMachine.handle(Action(keyEvent: .tab, originalEvent: nil, cursorPosition: .zero)))
+        wait(for: [expectation], timeout: 1.0)
+    }
+
     func testHandleSelectingEnter() {
         dictionary.setEntries(["と": [Word("戸")]])