Store the top scroll top in the document

demo/editor.html

@@ -34,7 +34,6 @@
 	#controls {
 		width: 100%;
 		height: 55px;
-		margin: 0;
 	}
   
 	</style>

src/Document.js

@@ -80,6 +80,18 @@ ace.Document.prototype.getMode = function() {
     return this._mode;
 };
 
+ace.Document.prototype._scrollTop = 0;
+ace.Document.prototype.setScrollTopRow = function(scrollTopRow) {
+    if (this._scrollTop === scrollTopRow) return;
+
+    this._scrollTop = scrollTopRow;
+    this.$dispatchEvent("changeScrollTop");
+};
+
+ace.Document.prototype.getScrollTopRow = function() {
+    return this._scrollTop;
+};
+
 ace.Document.prototype.getWidth = function() {
     if (this.modified) {
         this.modified = false;

src/Editor.js

@@ -38,6 +38,8 @@ ace.Editor.prototype.setDocument = function(doc) {
         var selection = this.doc.getSelection();
         this.selection.removeEventListener("changeCursor", this._onCursorChange);
         this.selection.removeEventListener("changeSelection", this._onSelectionChange);
+
+        this.doc.setScrollTopRow(this.renderer.getScrollTopRow());
     }
 
     this.doc = doc;
@@ -66,6 +68,7 @@ ace.Editor.prototype.setDocument = function(doc) {
     this.renderer.draw();
     this.onCursorChange();
     this.onSelectionChange();
+    this.renderer.scrollToRow(doc.getScrollTopRow());
 };
 
 ace.Editor.prototype.getDocument = function() {

src/VirtualRenderer.js

@@ -198,6 +198,10 @@ ace.VirtualRenderer.prototype.getScrollTop = function() {
     return this.scrollTop;
 };
 
+ace.VirtualRenderer.prototype.getScrollTopRow = function() {
+    return this.scrollTop / this.lineHeight;
+};
+
 ace.VirtualRenderer.prototype.scrollToRow = function(row) {
     this.scrollToY(row * this.lineHeight);
 };