Creating MQTT DataSource

[a3pl1]

Hi, I had decided to give a try to make production system based on SCADA-LTS connected to MQTT broker but I just stopped at the beginnig.
I can not add MQTT Datasource.
I have scada-lts version v2.7.7.3_1 where I can choose MQTT as a data source.
But, no matter what I do in that source config window, I can not save that source.
After clicking the save icon, it just starts to blink slowly and no other information or error.
Just blinking and nothing happens.

Any advice from You guys ?

[a3pl1]

Fixed after update to beta 2.8.