1. It need long time run of program. (need to open some picture then let it alone in background)
2. The tabs should as many as when the previous / next button show (In my case I don't open the pics in folderA.)

3. Must open two picture in a subfolder (just pass ctrl+r in the folderA. You must not enter folderB to open pictures)
e.g FolderA (Pass ctrl+r here and open FolderB's picture here)
|--------FolderB
4. Then minimum the program. (better to let it along for 6hours)
5. When time is up. Open some new pictures Other than folderA and folderB (should be outside of folderA)
6. Pass ESC. When the last tab closed it automatic changed to the nearest one. But the picture here is not what you opened.
You click the tab on the left tab which is another pictures in folderB But it also changed to another one.
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If it can be triggered successfully.
You just click the tab of the pictures in the folderB.(latest two tabs) And it should be changed to other picture.
Whatever you scroll up or down to change pics. You can't change it back. (the num on left bottom shows it don't including the pictures of folderB Which is the numbers of picture when you have not passed the ctrl+r)
Maybe the number on the left bottom can let you know when the time is up.( You better never click the latest two tabs, just use other tab to learn the situation )
But this need to change the things mentioned on number 2.
The picture it jumped to is always the left one when you see in (ctrl+r mode) and they are in folderA.
e.g The number of pictures when you passed ctrl+r is 120.
If the picture number is 9/120 and this one is belong to folderB
Then if bug happens the picture shown is same as the 8/120. (number on Left bottom won't be 8/120)
This is a old bug. It exist in old version.(I don't update it in long time) And still exist in newest version XnView MP 0.99.7