Antonis - is there a feedback with a test project for the issue you’ve described?
Alex - I have a work around that works for control events other then Open and Shown. Shown doesn’t seem to fire for controls on a WebToolbarContainer (another bug?). As for Open, that’s typical because the world just isn’t setup yet in Open. (Open doesn’t seem to be very reliable or useful in web apps.)
But it’s working in your feedback project for MouseUp.
I’m adding some notes to the module and then I’ll write a blog post and add the project to the feedback report.