u-he and ardour mixbus problem with arch/manjaro

Hi there,
I have a strange and hard to track down problem with Ardour/Mixbus and u-he zebra plugin on Manjaro linux, using the xfce desktop:

When i open the plugin and i want to make some changes, insert a new oscillator for example, the window pops up but as soon as i hover the mouse towards that direction it disappears and i cant make any changes… I tried with the same distro and bitwig and the plugin works just fine. I tried with the same ardour and mixbus versions on debian stable and it also just works fine… so it s hard to guess what might be the problem ;( any ideas? anyone else using manjaro and ardour ? thanks !

The first thing I’d ask is if you have the latest stable Ardour - 4.7. If not, a bug somewhere might have been fixed with an upgrade.

yes, it s ardour 4,7 , and same with the newest Mixbus 3.2.23