Update 3 6 action history

3-6-action-history.md

 # Undo & redo (and how to use Actions Pane)
 
-![](img/3--6-actions-pane.png)
+![](img/3-6-actions-pane.png)
 
 The **Actions Pane** displays the history of actions related to the current selected layer.
 If the selected layer is a default layer (background map layer, borderline layer), the **Actions Pane** shows the whole edit history of the **Rendering Pane**. For other types of grid layers, it only shows the edit history of the selected layer.
@@ -10,7 +10,7 @@ You can select an action entry in the action list and
 *  Click the *Undo* button or click the *Up* icon to undo the history entry to the former action entry. 
 *  Click the *Redo* button or click the *Down* icon to redo the history entry to the later action entry. 
    
-      ![](img/3--6-actions-pane.png)
+      ![](img/3-6-actions-pane.png)
 
 You can also select an action entry and right-click to select *Undo* or *Redo* options.