Newly added files doesn't generate thumbnails

[Zheitk]

1.- Open any folder
2.- Add a picture to that folder (using an external program, winxp)
3.- This happens:

2012-08-14 [18_56_01].png (65.61 KiB) Viewed 2056 times

It also happens after using XnViewMP move dialog:
1.- Enter the target folder
2.- Enter the filename of the moved file in the filter search.
In this case, double clicking the thumbnail~less picture will open it with the "Windows Picture and Fax Viewer"

[xnview]

Problem if 'create for whole folder' not active