Add coverGutterNextToScrollbar option

Issue #1493

Author: marijnh

doc/manual.html

@@ -232,6 +232,13 @@ <h2 id="config">Configuration</h2>
       horizontally (false) or whether it stays fixed during horizontal
       scrolling (true, the default).</dd>
 
+      <dt id="option_coverGutterNextToScrollbar"><code><strong>coverGutterNextToScrollbar</strong>: boolean</code></dt>
+      <dd>When <a href="#option_fixedGutter"><code>fixedGutter</code></a>
+      is on, and there is a horizontal scrollbar, by default the
+      gutter will be visible to the left of this scrollbar. If this
+      option is set to true, it will be covered by an element with
+      class <code>CodeMirror-gutter-filler</code>.</dd>
+
       <dt id="option_readOnly"><code><strong>readOnly</strong>: boolean|string</code></dt>
       <dd>This disables editing of the editor content by the user. If
       the special value <code>"nocursor"</code> is given (instead of

lib/codemirror.js

@@ -213,7 +213,7 @@ window.CodeMirror = (function() {
     estimateLineHeights(cm);
     regChange(cm);
     clearCaches(cm);
-    setTimeout(function(){updateScrollbars(cm.display, cm.doc.height, cm.options.fixedGutter);}, 100);
+    setTimeout(function(){updateScrollbars(cm);}, 100);
   }
 
   function estimateHeight(cm) {
@@ -251,6 +251,7 @@ window.CodeMirror = (function() {
 
   function guttersChanged(cm) {
     updateGutters(cm);
+    alignHorizontally(cm);
     regChange(cm);
   }
 
@@ -318,7 +319,8 @@ window.CodeMirror = (function() {
 
   // Re-synchronize the fake scrollbars with the actual size of the
   // content. Optionally force a scrollTop.
-  function updateScrollbars(d /* display */, docHeight, fixedGutter) {
+  function updateScrollbars(cm) {
+    var d = cm.display, docHeight = cm.doc.height;
     var totalHeight = docHeight + paddingVert(d);
     d.sizer.style.minHeight = d.heightForcer.style.top = totalHeight + "px";
     var scrollHeight = Math.max(totalHeight, d.scroller.scrollHeight);
@@ -340,7 +342,7 @@ window.CodeMirror = (function() {
       d.scrollbarFiller.style.display = "block";
       d.scrollbarFiller.style.height = d.scrollbarFiller.style.width = scrollbarWidth(d.measure) + "px";
     } else d.scrollbarFiller.style.display = "";
-    if (needsH && fixedGutter) {
+    if (needsH && cm.options.coverGutterNextToScrollbar && cm.options.fixedGutter) {
       d.gutterFiller.style.display = "block";
       d.gutterFiller.style.height = scrollbarWidth(d.measure) + "px";
       d.gutterFiller.style.width = d.gutters.offsetWidth + "px";
@@ -410,7 +412,7 @@ window.CodeMirror = (function() {
           signalLater(cm, "viewportChange", cm, cm.display.showingFrom, cm.display.showingTo);
       } else break;
       updateSelection(cm);
-      updateScrollbars(cm.display, cm.doc.height, cm.options.fixedGutter);
+      updateScrollbars(cm);
 
       // Clip forced viewport to actual scrollable area
       if (viewPort)
@@ -3123,6 +3125,7 @@ window.CodeMirror = (function() {
     cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0";
     cm.refresh();
   }, true);
+  option("coverGutterNextToScrollbar", false, updateScrollbars);
   option("lineNumbers", false, function(cm) {
     setGuttersForLineNumbers(cm.options);
     guttersChanged(cm);