Fix bugs with new activeSelection (#4167)

* test

* fixes

src/mixins/canvas_events.mixin.js

@@ -543,7 +543,8 @@
         target = this._activeObject;
       }
 
-      if (this.selection && (!target || (!target.selectable && !target.isEditing))) {
+      if (this.selection && (!target ||
+        (!target.selectable && !target.isEditing && target !== this._activeObject))) {
         this._groupSelector = {
           ex: pointer.x,
           ey: pointer.y,
@@ -553,16 +554,13 @@
       }
 
       if (target) {
-        if (target.selectable && (target.__corner || !shouldGroup)) {
+        if ((target.selectable || target === this._activeObject) && (target.__corner || !shouldGroup)) {
           this._beforeTransform(e, target);
           this._setupCurrentTransform(e, target);
         }
         if (target.selectable) {
           this.setActiveObject(target, e);
         }
-        else {
-          this.discardActiveObject();
-        }
       }
       this._handleEvent(e, 'down', target ? target : null);
       // we must renderAll so that we update the visuals

src/mixins/canvas_grouping.mixin.js

@@ -13,7 +13,7 @@
      */
     _shouldGroup: function(e, target) {
       var activeObject = this._activeObject;
-      return e[this.selectionKey] && target && target.selectable && this.selection &&
+      return activeObject && e[this.selectionKey] && target && target.selectable && this.selection &&
             (activeObject !== target || activeObject.type === 'activeSelection');
     },
 
@@ -24,7 +24,7 @@
      */
     _handleGrouping: function (e, target) {
       var activeObject = this._activeObject;
-      if (activeObject.__corner !== 0) {
+      if (activeObject.__corner) {
         return;
       }
       if (target === activeObject) {

src/shapes/object.class.js

@@ -545,6 +545,16 @@
      */
     dirty:                true,
 
+    /**
+     * keeps the value of the last hovered coner during mouse move.
+     * 0 is no corner, or 'mt', 'ml', 'mtr' etc..
+     * It should be private, but there is no harm in using it as
+     * a read-only property.
+     * @type number|string|any
+     * @default 0
+     */
+    __corner: 0,
+
     /**
      * List of properties to consider when checking if state
      * of an object is changed (fabric.Object#hasStateChanged)

test/unit/canvas.js

@@ -1812,13 +1812,18 @@
     rect.selectable = false;
     canvas.__onMouseUp(e);
     canvas.__onMouseDown(e);
-    deepEqual(canvas._groupSelector, expectedGroupSelector, 'with object non selectable groupSelector is started');
+    deepEqual(canvas._groupSelector, null, 'with object non selectable but already selected groupSelector is not started');
     canvas.__onMouseUp(e);
+    canvas.discardActiveObject();
     rect.isEditing = true;
-    canvas.__onMouseUp(e);
     canvas.__onMouseDown(e);
     deepEqual(canvas._groupSelector, null, 'with object editing, groupSelector is not started');
     canvas.__onMouseUp(e);
+    canvas.discardActiveObject();
+    rect.isEditing = false;
+    canvas.__onMouseDown(e);
+    deepEqual(canvas._groupSelector, expectedGroupSelector, 'a new groupSelector is created');
+    canvas.__onMouseUp(e);
   });
 
   test('mouse:up isClick = true', function() {