in Tools > Options > General
check Libreoffice dialogs
Ctrl+O of File > Open
> No dialog shown
Build ID: b6da6a887a0417be02e123a6d19837123e58b94f
TinderBox: Linux-rpm_deb-x86@45-TDF, Branch:master, Time: 2014-08-09_07:47:21
The fix of Bug 78845 fixed this also, please try with a newer build.
*** This bug has been marked as a duplicate of bug 78845 ***