Merge branch 'enhancements/tree-view-checked-state' into enhancements/changes-tree-view

Author: StanleyGoldman

src/UnityExtension/Assets/Editor/GitHub.Unity/UI/TreeControl.cs

@@ -283,6 +283,10 @@ private void ToggleNodeChecked(int idx, TreeNode node)
                 {
                     checkedFileNodes.Add(node.Path, node);
                 }
+                else
+                {
+                    checkedFileNodes.Remove(node.Path);
+                }
             }
 
             ToggleParentFoldersChecked(idx, node, isChecked);
@@ -310,6 +314,10 @@ private void ToggleChildrenChecked(int idx, TreeNode node, bool isChecked)
                     {
                         checkedFileNodes.Add(node.Path, node);
                     }
+                    else
+                    {
+                        checkedFileNodes.Remove(node.Path);
+                    }
                 }
             }
         }