So, add the element to your layout, then go to the live preview and click the button.
Now, go back into edit mode and your popup will stay open and you can edit it.
I prefer to use the modals (🎈 New Images, Popups & Toasts) since its all customizable and I can control the open/close and display/hide properties a little easier.
The difficulty is that without the element being in the hierarchy navigator - it’s more difficult to organize the layout and deal with conditional display on children elements (if you accidentally make display = false, it’s irreversible since you can’t select the element anymore)
I may have to setup a modal instead to make this manageable - just slightly bit more work
No, the popup element is a legacy element we don’t recommend using. We will develop a new one with better UX but, in the meantime, we recommend using the modals or toast templates: