I tried today with v0.9.13.11git.11cf37, your package and self compiled (the only difference my version is built without vst3 support). Sadly, it didn't help.
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I start with an empty project and I import a drum midi track (35 kb). Bus settings "master" -> "master". Connections are set via qjackctl (also tried your versions) to qsynth (also tried your version) and it works like a charm as I am used to it :-)
Now I add a second midi track and leave it empty. Double clicking on the tracks pane opens the settings dialog. I create a new bus and call it e.g. "FluidSynth". Bus settings "FluidSynth" -> "Master". I do not add any midi events. Switching between the options in the drop down lists of "input bus" and "output bus" several times (FluidSynth -> FluidSynth, Master -> FluidSynth, Master -> Master, ...) makes Qtractor crash :-( even without loading any lv2-plugins which was my first suspect. Qtractor is not in play modus.
Changing the desktop theme didn't help either (gtk suspected issue).
The terminal always reports "memory access error". I don't think it's a hardware defect, becaus e.g. Ardour and Rosegarden perform stable in the same system.
I tried today with v0.9.13.11git.11cf37, your package and self compiled (the only difference my version is built without vst3 support). Sadly, it didn't help.
=================
I start with an empty project and I import a drum midi track (35 kb). Bus settings "master" -> "master". Connections are set via qjackctl (also tried your versions) to qsynth (also tried your version) and it works like a charm as I am used to it :-)
Now I add a second midi track and leave it empty. Double clicking on the tracks pane opens the settings dialog. I create a new bus and call it e.g. "FluidSynth". Bus settings "FluidSynth" -> "Master". I do not add any midi events. Switching between the options in the drop down lists of "input bus" and "output bus" several times (FluidSynth -> FluidSynth, Master -> FluidSynth, Master -> Master, ...) makes Qtractor crash :-( even without loading any lv2-plugins which was my first suspect. Qtractor is not in play modus.
Changing the desktop theme didn't help either (gtk suspected issue).
The terminal always reports "memory access error". I don't think it's a hardware defect, becaus e.g. Ardour and Rosegarden perform stable in the same system.
Greetings, Michael