No tabs displayed when importing a GP file

When loading a Guitar Pro File with a guitar track the tabs are not displayed at all.

Steps to reproduce:
1. Open MuseScore
2. Open a Guitar Pro file containing a guitar track

Expected:
Fret numbers are shown in the Tab-part

Actual:
The Tab-part is empty

MuseScore version: https://github.com/musescore/MuseScore/commit/b4b960c09558701cee75a900a…

OS:
Sabayon Linux with Kernel 3.8.5
64 Bit