When soft wrap is on, don't position hidden input beyond width of horizontal scroller.

spec/atom/editor-spec.coffee

@@ -174,6 +174,15 @@ describe "Editor", ->
       it "moves the hidden input element to the position of the cursor to prevent scrolling misbehavior", ->
         expect(editor.hiddenInput.position()).toEqual(top: 2 * editor.lineHeight, left: 2 * editor.charWidth)
 
+      describe "if soft-wrap is enabled", ->
+        beforeEach ->
+          setEditorWidthInChars(editor, 20)
+          editor.setSoftWrap(true)
+
+        it "doesn't move the hidden input beyond the right side of the horizontal scroller to prevent chrome from auto-scrolling", ->
+          editor.setCursorScreenPosition([4, 20])
+          expect(editor.hiddenInput.position()).toEqual(top: 4 * editor.lineHeight, left: editor.horizontalScroller.width() - editor.charWidth)
+
     describe "when the arrow keys are pressed", ->
       it "moves the cursor by a single row/column", ->
         editor.trigger keydownEvent('right')
@@ -569,7 +578,6 @@ describe "Editor", ->
           expect(editor.buffer.lineForRow(5)).toEqual("    }")
           expect(editor.getCursorBufferPosition().column).toBe 5
 
-
   describe "selection", ->
     selection = null
 

src/atom/editor.coffee

@@ -120,7 +120,10 @@ class Editor extends View
       @insertText(e.originalEvent.data)
 
     @on 'cursor:position-changed', =>
-      @hiddenInput.css(@pixelPositionForScreenPosition(@cursor.getScreenPosition()))
+      position = @pixelPositionForScreenPosition(@cursor.getScreenPosition())
+      if @softWrap
+        position.left = Math.min(position.left, @horizontalScroller.width() - @charWidth)
+      @hiddenInput.css(position)
 
     @one 'attach', =>
       @calculateDimensions()