I always could use 'okular --unique foo.pdf' to open foo.pdf. Since about 1 to 2 weeks, this does not work anymore. The okular command just seems to hang, foo.pdf is not opened. However, 'okular foo.pdf' works just fine.

Reproducible: Always

Steps to Reproduce:
1. in the terminal, type: okular --unique foo.pdf
2. hit Enter (nothing happens / foo.pdf not opened)


Actual Results:  
mhofert@sklar:~/Desktop$ okular --unique foo.pdf
^C
=> aborted manually after several min.

Expected Results:  
open foo.pdf

Note: this always worked until recently (maybe about 1--2 weeks ago). Probably an Ubuntu update (sudo apt-get update/upgrade) caused the change (?). I work unter Ubuntu 13.04 on a Lenovo X1 Carbon.