fix issue on rotation undo

src/svgcanvas/selection.js

@@ -402,7 +402,11 @@ export const setRotationAngle = function (val, preventUndo) {
     // we need to undo it, then redo it so it can be undo-able! :)
     // TODO: figure out how to make changes to transform list undo-able cross-browser?
     const newTransform = elem.getAttribute('transform');
-    elem.setAttribute('transform', oldTransform);
+    if (oldTransform) {
+      elem.setAttribute('transform', oldTransform);
+    } else {
+      elem.removeAttribute('transform');
+    }
     selectionContext_.getCanvas().changeSelectedAttribute('transform', newTransform, selectedElements);
     selectionContext_.getCanvas().call('changed', selectedElements);
   }

src/svgcanvas/undo.js

@@ -188,7 +188,11 @@ export const changeSelectedAttributeNoUndoMethod = function (attr, newValue, ele
         // }
       } else if (attr === '#href') {
         setHref(elem, newValue);
-      } else { elem.setAttribute(attr, newValue); }
+      } else if (newValue) {
+        elem.setAttribute(attr, newValue);
+      } else {
+        elem.removeAttribute(attr);
+      }
 
       // Go into "select" mode for text changes
       // NOTE: Important that this happens AFTER elem.setAttribute() or else attributes like