開啟 resource.rc 一直顯示 opened in another editor

出現此 error，但是 resource.rc 並沒有被其它 editor 打開

解法是刪除隱藏檔 .suo，會讓該 solution 變成不開啟所有檔，便解決

MS 的回應：

Hi,

Thanks for the investigation and feedback. Before you figured out what the problem was, I was going to suggest that you delete your .suo file. This file is automatically created in your solution directory and is hidden by default. Among other user-specific solution state information, one of the items it tracks are the files that you last had open for a solution. Therefore, if you delete it, the next time you open that solution, no files will automatically be opened and it would have resolved your issue as well. We are not able to address this for the next version of Visual Studio but we'll consider improving this experience in a future release. 

Thanks again,
Jim Griesmer
Visual C++ Team