diff --git a/examples/images/index.js b/examples/images/index.js
index 49ef91b3a..03f80355f 100644
--- a/examples/images/index.js
+++ b/examples/images/index.js
@@ -178,6 +178,7 @@ class Images extends React.Component {
   onDropNode = (e, data, state) => {
     return state
       .transform()
+      .unsetSelection()
       .removeNodeByKey(data.node.key)
       .moveTo(data.target)
       .insertBlock(data.node)
diff --git a/package.json b/package.json
index e27b75c4b..5f032cb7d 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "slate",
   "description": "A completely customizable framework for building rich text editors.",
-  "version": "0.14.3",
+  "version": "0.14.4",
   "license": "MIT",
   "repository": "git://github.com/ianstormtaylor/slate.git",
   "main": "./lib/index.js",
diff --git a/src/models/text.js b/src/models/text.js
index fde1a2745..738ecd35f 100644
--- a/src/models/text.js
+++ b/src/models/text.js
@@ -287,14 +287,14 @@ class Text extends new Record(DEFAULTS) {
    */
 
   updateMark(index, length, mark, properties) {
+    const m = mark.merge(properties)
     const characters = this.characters.map((char, i) => {
       if (i < index) return char
       if (i >= index + length) return char
       let { marks } = char
-      const j = marks.indexOf(mark)
-      let m = marks.get(j)
-      m = m.merge(properties)
-      marks = marks.set(j, m)
+      if (!marks.has(mark)) return char
+      marks = marks.remove(mark)
+      marks = marks.add(m)
       char = char.merge({ marks })
       return char
     })
diff --git a/test/transforms/fixtures/by-key/set-mark-by-key/set-data/index.js b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/index.js
new file mode 100644
index 000000000..9c2a24bb3
--- /dev/null
+++ b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/index.js
@@ -0,0 +1,21 @@
+
+export default function (state) {
+  const { document, selection } = state
+  const first = document.getTexts().first()
+
+  return state
+    .transform()
+    .setMarkByKey(
+      first.key,
+      0,
+      first.length,
+      {
+        type: 'bold',
+        data: { key: true }
+      },
+      {
+        data: { key: false }
+      }
+    )
+    .apply()
+}
diff --git a/test/transforms/fixtures/by-key/set-mark-by-key/set-data/input.yaml b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/input.yaml
new file mode 100644
index 000000000..bc54126ff
--- /dev/null
+++ b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/input.yaml
@@ -0,0 +1,12 @@
+
+nodes:
+  - kind: block
+    type: paragraph
+    nodes:
+      - kind: text
+        ranges:
+          - text: word
+            marks:
+              - type: bold
+                data:
+                  key: true
diff --git a/test/transforms/fixtures/by-key/set-mark-by-key/set-data/output.yaml b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/output.yaml
new file mode 100644
index 000000000..88518e9d8
--- /dev/null
+++ b/test/transforms/fixtures/by-key/set-mark-by-key/set-data/output.yaml
@@ -0,0 +1,12 @@
+
+nodes:
+  - kind: block
+    type: paragraph
+    nodes:
+      - kind: text
+        ranges:
+          - text: word
+            marks:
+              - type: bold
+                data:
+                  key: false