diff --git a/package-lock.json b/package-lock.json
index b4997cd..5bb2faf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@github/file-attachment-element",
-  "version": "2.0.1",
+  "version": "3.0.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "@github/file-attachment-element",
-      "version": "2.0.1",
+      "version": "3.0.0",
       "license": "MIT",
       "devDependencies": {
         "@github/prettier-config": "0.0.4",
diff --git a/package.json b/package.json
index 12de877..0db9814 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@github/file-attachment-element",
-  "version": "2.0.1",
+  "version": "3.0.0",
   "description": "Attach files via drag and drop or file input.",
   "main": "dist/index.umd.js",
   "module": "dist/index.js",
diff --git a/src/attachment.ts b/src/attachment.ts
index 892c2cb..1c8c6ab 100644
--- a/src/attachment.ts
+++ b/src/attachment.ts
@@ -43,6 +43,10 @@ export default class Attachment {
     return ['image/gif', 'image/png', 'image/jpg', 'image/jpeg'].indexOf(this.file.type) > -1
   }
 
+  isVideo(): boolean {
+    return ['video/mp4', 'video/quicktime'].indexOf(this.file.type) > -1
+  }
+
   saving(percent: number): void {
     if (this.state !== 'pending' && this.state !== 'saving') {
       throw new Error(`Unexpected transition from ${this.state} to saving`)
diff --git a/src/file-attachment-element.ts b/src/file-attachment-element.ts
index 119b027..286b0af 100644
--- a/src/file-attachment-element.ts
+++ b/src/file-attachment-element.ts
@@ -73,6 +73,7 @@ function onDragenter(event: DragEvent) {
   if (dragging) {
     clearTimeout(dragging)
   }
+
   dragging = window.setTimeout(() => target.removeAttribute('hover'), 200)
 
   const transfer = event.dataTransfer
@@ -81,7 +82,6 @@ function onDragenter(event: DragEvent) {
   transfer.dropEffect = 'copy'
   target.setAttribute('hover', '')
 
-  event.stopPropagation()
   event.preventDefault()
 }
 
diff --git a/test/test.js b/test/test.js
index 411092c..1b27583 100644
--- a/test/test.js
+++ b/test/test.js
@@ -39,6 +39,24 @@ describe('file-attachment', function () {
       assert(attachment.isImage())
     })
 
+    it('detects mp4 video types', function () {
+      const file = new File(['hubot'], 'test.mp4', {type: 'video/mp4'})
+      const attachment = new Attachment(file)
+      assert(attachment.isVideo())
+    })
+
+    it('detects quicktime video types', function () {
+      const file = new File(['hubot'], 'test.mov', {type: 'video/quicktime'})
+      const attachment = new Attachment(file)
+      assert(attachment.isVideo())
+    })
+
+    it('detects non video types', function () {
+      const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
+      const attachment = new Attachment(file)
+      assert(!attachment.isVideo())
+    })
+
     it('transitions through save states', function () {
       const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
       const attachment = new Attachment(file)
@@ -124,6 +142,36 @@ describe('file-attachment', function () {
       assert.equal('test.png', event.detail.attachments[0].file.name)
       assert.equal(0, input.files.length)
     })
+
+    it('bubbles the dragenter event after cancelling its default behavior', async function () {
+      const dataTransfer = new DataTransfer()
+      const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
+      dataTransfer.items.add(file)
+
+      const dragEvent = new DragEvent('dragenter', {bubbles: true, cancelable: true, dataTransfer})
+
+      const listener = once('dragenter')
+      input.dispatchEvent(dragEvent)
+
+      const event = await listener
+      assert.equal(dragEvent, event)
+      assert.equal(true, event.defaultPrevented)
+    })
+
+    it('bubbles the dragover event after cancelling its default behavior', async function () {
+      const dataTransfer = new DataTransfer()
+      const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
+      dataTransfer.items.add(file)
+
+      const dragEvent = new DragEvent('dragover', {bubbles: true, cancelable: true, dataTransfer})
+
+      const listener = once('dragover')
+      input.dispatchEvent(dragEvent)
+
+      const event = await listener
+      assert.equal(dragEvent, event)
+      assert.equal(true, event.defaultPrevented)
+    })
   })
 })