Changing the close icon when the tab is modified

src/packages/tabs/src/tab.coffee

@@ -11,6 +11,26 @@ class Tab extends View
     @updateFileName()
     @editSession.on 'buffer-path-change.tab', =>
       @updateFileName()
+    @subscribeToBuffer()
+
+  updateTab: ->
+    @updateBufferHasModifiedText(@buffer.isModified())
+
+  subscribeToBuffer: ->
+    @buffer?.off '.tabs'
+    @buffer = @editSession.buffer
+    @buffer.on 'contents-modified.tabs', (e) => @updateBufferHasModifiedText(e.differsFromDisk)
+    @buffer.on 'after-save.tabs', => @updateTab()
+    @buffer.on 'git-status-change.tabs', => @updateTab()
+    @updateTab()
+
+  updateBufferHasModifiedText: (differsFromDisk) ->
+    if differsFromDisk
+      @toggleClass('file-modified') unless @isModified
+      @isModified = true
+    else
+      @removeClass('file-modified') if @isModified
+      @isModified = false
 
   updateFileName: ->
     @fileName.text(@editSession.buffer.getBaseName() ? 'untitled')

src/packages/tabs/src/tabs.css

@@ -21,6 +21,20 @@
   height: 24px;
 }
 
+.tab.file-modified .close-icon {
+  box-shadow: inset 0 1px 2px #333;
+  background-color: #F9EE98;
+  top: 8px;
+  border-radius: 10px;
+  width: 7px;
+  height: 7px;
+  right: 7px;
+}
+
+.tab.file-modified .close-icon:before {
+  content: "";
+}
+
 .tab:first-child {
   box-shadow: inset 0 0 5px #383838, 0 1px 0 #585858, inset -1px 0 0 #4a4a4a;
 }