Respect horizontal scrollbar when rendering the vertical, and vice versa

We set overflow to hidden in the opposite scroll direction only if we
can't actually scroll in that direction, causing the white square where
neither scrollbar overlaps to appear at the lower right corner.

spec/editor-component-spec.coffee

@@ -547,6 +547,26 @@ describe "EditorComponent", ->
       bottomOfEditor = node.getBoundingClientRect().bottom
       expect(bottomOfLastLine).toBe bottomOfEditor
 
+    it "assigns the overflow to 'hidden' in the opposite direction unless the editor scrollable in that direction", ->
+      expect(verticalScrollbarNode.style.overflowX).toBe 'hidden'
+      expect(horizontalScrollbarNode.style.overflowY).toBe 'hidden'
+      return
+
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+      expect(verticalScrollbarNode.style.overflowX).toBe 'hidden'
+      expect(horizontalScrollbarNode.style.overflowY).toBe ''
+
+      node.style.width = 10 * charWidth + 'px'
+      component.measureHeightAndWidth()
+      expect(verticalScrollbarNode.style.overflowX).toBe ''
+      expect(horizontalScrollbarNode.style.overflowY).toBe ''
+
+      node.style.height = 20 * lineHeightInPixels + 'px'
+      component.measureHeightAndWidth()
+      expect(verticalScrollbarNode.style.overflowX).toBe ''
+      expect(horizontalScrollbarNode.style.overflowY).toBe 'hidden'
+
     describe "when a mousewheel event occurs on the editor", ->
       it "updates the horizontal or vertical scrollbar depending on which delta is greater (x or y)", ->
         node.style.height = 4.5 * lineHeightInPixels + 'px'

src/display-buffer.coffee

@@ -123,9 +123,14 @@ class DisplayBuffer extends Model
   horizontallyScrollable: ->
     not @getSoftWrap() and @getScrollWidth() > @getWidth()
 
+  verticallyScrollable: ->
+    @getScrollHeight() > @getClientHeight()
+
   getHorizontalScrollbarHeight: -> 15
 
-  getWidth: -> @width ? @getScrollWidth()
+  getWidth: ->
+    @width ? @getScrollWidth()
+
   setWidth: (newWidth) ->
     oldWidth = @width
     @width = newWidth
@@ -149,6 +154,8 @@ class DisplayBuffer extends Model
   setScrollLeft: (scrollLeft) ->
     if @manageScrollPosition
       @scrollLeft = Math.max(0, Math.min(@getScrollWidth() - @getWidth(), scrollLeft))
+      console.log @scrollLeft
+      @scrollLeft
     else
       @scrollLeft = scrollLeft
 

src/editor-component.coffee

@@ -55,6 +55,7 @@ EditorComponent = React.createClass
         onScroll: @onVerticalScroll
         scrollTop: scrollTop
         scrollHeight: scrollHeight
+        scrollableInOppositeDirection: editor.horizontallyScrollable() if @isMounted()
 
       ScrollbarComponent
         ref: 'horizontalScrollbar'
@@ -63,6 +64,7 @@ EditorComponent = React.createClass
         onScroll: @onHorizontalScroll
         scrollLeft: scrollLeft
         scrollWidth: scrollWidth
+        scrollableInOppositeDirection: editor.verticallyScrollable() if @isMounted()
 
   getRenderedRowRange: ->
     renderedRowRange = @props.editor.getVisibleRowRange()

src/editor-scroll-view-component.coffee

@@ -182,17 +182,19 @@ EditorScrollViewComponent = React.createClass
   measureHeightAndWidth: ->
     return unless @isMounted()
 
-    node = @getDOMNode()
-    computedStyle = getComputedStyle(node)
     {editor} = @props
+    node = @getDOMNode()
+    editorNode = node.parentNode
+    {position} = getComputedStyle(editorNode)
+    {width, height} = editorNode.style
 
-    unless computedStyle.height is '0px'
-      clientHeight = node.clientHeight
+    if position is 'absolute' or height
+      clientHeight =  node.clientHeight
       editor.setHeight(clientHeight) if clientHeight > 0
 
-    unless computedStyle.width is '0px'
+    if position is 'absolute' or width
       clientWidth = node.clientWidth
-      editor.setWidth(clientWidth) if clientHeight > 0
+      editor.setWidth(clientWidth) if clientWidth > 0
 
   focus: ->
     @refs.input.focus()

src/editor.coffee

@@ -1851,6 +1851,8 @@ class Editor extends Model
   setHeight: (height) -> @displayBuffer.setHeight(height)
   getHeight: -> @displayBuffer.getHeight()
 
+  getClientHeight: -> @displayBuffer.getClientHeight()
+
   setWidth: (width) -> @displayBuffer.setWidth(width)
   getWidth: -> @displayBuffer.getWidth()
 
@@ -1889,6 +1891,10 @@ class Editor extends Model
 
   scrollToBufferPosition: (bufferPosition) -> @displayBuffer.scrollToBufferPosition(bufferPosition)
 
+  horizontallyScrollable: -> @displayBuffer.horizontallyScrollable()
+
+  verticallyScrollable: -> @displayBuffer.verticallyScrollable()
+
   # Deprecated: Call {::joinLines} instead.
   joinLine: ->
     deprecate("Use Editor::joinLines() instead")

src/scrollbar-component.coffee

@@ -1,13 +1,20 @@
 React = require 'react'
 {div} = require 'reactionary'
-{isEqualForProperties} = require 'underscore-plus'
+{extend, isEqualForProperties} = require 'underscore-plus'
 
 module.exports =
 ScrollbarComponent = React.createClass
   render: ->
-    {orientation, className, scrollHeight, scrollWidth} = @props
+    {orientation, className, scrollHeight, scrollWidth, scrollableInOppositeDirection} = @props
 
-    div {className, @onScroll},
+    style = {}
+    switch orientation
+      when 'vertical'
+        style.overflowX = 'hidden' unless scrollableInOppositeDirection
+      when 'horizontal'
+        style.overflowY = 'hidden' unless scrollableInOppositeDirection
+
+    div {className, style, @onScroll},
       switch orientation
         when 'vertical'
           div className: 'scrollbar-content', style: {height: scrollHeight}
@@ -23,9 +30,9 @@ ScrollbarComponent = React.createClass
   shouldComponentUpdate: (newProps) ->
     switch @props.orientation
       when 'vertical'
-        not isEqualForProperties(newProps, @props, 'scrollHeight', 'scrollTop')
+        not isEqualForProperties(newProps, @props, 'scrollHeight', 'scrollTop', 'scrollableInOppositeDirection')
       when 'horizontal'
-        not isEqualForProperties(newProps, @props, 'scrollWidth', 'scrollLeft')
+        not isEqualForProperties(newProps, @props, 'scrollWidth', 'scrollLeft', 'scrollableInOppositeDirection')
 
   componentDidUpdate: ->
     {orientation, scrollTop, scrollLeft} = @props

static/editor.less

@@ -24,7 +24,6 @@
 
     height: 15px;
     overflow-x: auto;
-    overflow-y: hidden;
     z-index: 3;
 
     .scrollbar-content {