Version: (using KDE 4.4.0) OS: Linux Installed from: openSUSE RPMs Okular has an excellent feature: it automatically notices changes to opened files and re-loads them. Unfortunately this feature has a bug: if the new file is somehow unreadable, it means the "old" file is lost. For example if I open a pdf file, and then using the shell or dolphin I take away its read permissions, okular automatically reloads to an empty window, which I think is a bug -- it should not unload the old file until it is sure that there is still something to be displayed. Another example is using open-with within firefox: firefox saves a file to /tmp, and then opens okular. If you then close firefox, it cleans the file in /tmp, and the okular window becomes empty too.
*** This bug has been marked as a duplicate of bug 225907 ***