Comment 3 for bug 1475391

I can confirm. Have the same behaviour after last update plank to 0.9.1.1345. System - Xubuntu 15.04 x64.
Plank hide mode configured to intellectual hidie. But after few time it stopping showing up. And plank not crashed at that moment (process is working and displaying in "ps aux | grep plank").
This issue wasn't exists in previous version. Is it possible to donwgrade package?

p.s. Sorry for my english.