xfce4-panel plugin crashes when using vala-panel-appenu and vscode

This issue is already fixed in the latest release of the Vala-appmenu 0.7.6 (fix I believe was added to 0.7.5, but fossfreedom may have identified an additional one). Ubuntu Budgie has just backported some of the commits, which ones I am not sure, but I think it was all of 0.7.5 & one other related to fixing a build from source issue, @fossfreedom added them a little while ago.