lxde - Run synapse (or alternative) on Lubuntu 15.04

On Lununtu 15.04 I installed synapse via PPA:

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:synapse-core/testing
sudo apt-get update
sudo apt-get install synapse

Source: http://linuxg.net/how-to-install-synapse-0-2-99-on-ubuntu-15-04-ubuntu-14-10-ubuntu-14-04-and-derivatives/

It seems to run, but it crashes the moment I enter any letter into the window.

How can I make this run or is there an alternative on Lubuntu with lxde?

Maybe it would suffice to start the execute-command from your menu with

Alt F1