Items that you have checked out (for example, when changing them) are locked by you and other users cannot edit these items. A red check mark identifies items that you have checked out. When you have finished editing an item, you can check it in to make it available for other users to edit. You can also check in all items at the same time by right-clicking the solution and selecting Check In All Files. Items checked out by other users are identified by a blue user icon. The Properties window displays the user that has checked out the items.
简而言之，如果user A checkout了某个资源，则其他user无法再编辑该资源，直至user A checkin为止。
某个资源被checkout之后，在Cloud Application Studio里会显示一个红色的小勾。
user完成编辑后，需点击check in 按钮，这样其他user才能继续编辑。
