diff --git a/README.md b/README.md
index 18b3bf3a..b7da233d 100644
--- a/README.md
+++ b/README.md
@@ -64,9 +64,13 @@ Open cmd and go to [labelImg]
 2. Click 'Change default saved annotation folder' in Menu/File
 3. Click 'Open Dir'
 4. Click 'Create RectBox'
+5. Click and release left mouse to select a region to annotate the rect box
+6. You can use right mouse to drag the rect box to copy or move it
 
 The annotation will be saved to the folder you specify.
 
+You can refer to the below hotkeys to speed up your workflow.
+
 ### Create pre-defined classes
 
 You can edit the [data/predefined_classes.txt](https://github.com/tzutalin/labelImg/blob/master/data/predefined_classes.txt) to load pre-defined classes
@@ -75,11 +79,16 @@ You can edit the [data/predefined_classes.txt](https://github.com/tzutalin/label
 
 |          |                                          |
 |----------|------------------------------------------|
+| Ctrl + u | Load all of the images from a directory  |
 | Ctrl + r | Change the default annotation target dir |
 | Ctrl + s | Save                                     |
-| w        | Create a bounding box                    |
+| Ctrl + d | Copy the current label and rect box      |
+| w        | Create a rect box                        |
 | d        | Next image                               |
 | a        | Previous image                           |
+| del      | Delete the selected rect box             |
+| Ctrl++   | Zoom in                                  |
+| Ctrl--   | Zoom out                                 |
 
 ### How to contribute
 Send a pull request
diff --git a/labelImg.py b/labelImg.py
index d7b0243e..eac0ac76 100755
--- a/labelImg.py
+++ b/labelImg.py
@@ -633,6 +633,9 @@ class MainWindow(QMainWindow, WindowMixin):
             action.setEnabled(True)
 
     def remLabel(self, shape):
+        if shape is None:
+            # print('rm empty label')
+            return
         item = self.shapesToItems[shape]
         self.labelList.takeItem(self.labelList.row(item))
         del self.shapesToItems[shape]
diff --git a/libs/shape.py b/libs/shape.py
index 3bf5c1e8..fba1863b 100644
--- a/libs/shape.py
+++ b/libs/shape.py
@@ -58,7 +58,6 @@ class Shape(object):
             self.line_color = line_color
 
     def close(self):
-        assert len(self.points) > 2
         self._closed = True
 
     def reachMaxPoints(self):
@@ -163,7 +162,7 @@ class Shape(object):
         self._highlightIndex = None
 
     def copy(self):
-        shape = Shape("Copy of %s" % self.label)
+        shape = Shape("%s" % self.label)
         shape.points = [p for p in self.points]
         shape.fill = self.fill
         shape.selected = self.selected