Ticket #36482: 36482.6.patch

src/wp-admin/js/editor-expand.js

@@ -16 +16 @@
                         $textTop = $( '#ed_toolbar' ),
                         $textEditor = $( '#content' ),
                         textEditor = $textEditor[0],
-                        textEditorLength = 0,
                         $bottom = $( '#post-status-info' ),
                         $menuBar = $(),
                         $statusBar = $(),
@@ -76 +75 @@
                 }
 
                 function textEditorResize() {
-                        var reduce, scrollHeight;
+                        var height;
+                        var length;
+                        var scrollHeight;
 
                         if ( mceEditor && ! mceEditor.isHidden() ) {
                                 return;
@@ -86 +87 @@
                                 return;
                         }
 
-                        reduce = textEditorLength > ( textEditorLength = textEditor.value.length );
-                        scrollHeight = textEditor.scrollHeight;
+                        height = parseInt( textEditor.style.height, 10 );
+                        length = textEditor.value.length;
 
-                        if ( reduce ) {
+                        if ( length < textEditorResize.oldLength ) {
                                 textEditor.style.height = 'auto';
-                                textEditor.style.height = scrollHeight + 'px';
-                                adjust();
-                        } else if ( parseInt( textEditor.style.height, 10 ) < scrollHeight ) {
-                                textEditor.style.height = scrollHeight + 'px';
+                                scrollHeight = textEditor.scrollHeight;
+
+                                if ( scrollHeight < autoresizeMinHeight ) {
+                                        textEditor.style.height = autoresizeMinHeight + 'px';
+                                } else {
+                                        textEditor.style.height = scrollHeight + 'px';
+                                }
+
+                                // When reducing the height, scroll up the difference.
+                                if ( scrollHeight - height < 0 ) {
+                                        window.scrollBy( 0, scrollHeight - height );
+                                }
+
                                 adjust();
+                        } else {
+                                scrollHeight = textEditor.scrollHeight;
+
+                                if ( height < scrollHeight ) {
+                                        textEditor.style.height = scrollHeight + 'px';
+                                        adjust();
+                                }
                         }
+
+                        textEditorResize.oldLength = length;
                 }
 
                 // We need to wait for TinyMCE to initialize.