How Can I Display Multiple Popups at the Same Time?
Stackable Popups Setting
By default, when a popup opens while another popup is already displayed, the currently displayed popup will disappear so that other popup can now be displayed.
However, you can overwrite this default setting so that you could display as many popups at the same as you like.
In the WordPress Admin, head to the popup(s) you want to make stackable and look for Display Settings in the Popup Editor. Under the Position Section, simply check the box to make the popup stackable. This popup will now stay open if another popup is triggered.
Z-Index Values Must Be Adjusted
Whether you're creating a special effects popup or properly planning in case multiple popups are triggered, it's important to make sure your z-index values are matched appropriately with your stackable popups to achieve your goals.
If your stackable popups all have the same z-index values, it will not work as intended. Your Z-Index values are simply a number that correlates to a "layer", if you will.
The popup you want to be on top of the others should always have the highest z-index, and by default, all popups are set to the highest possible z-index values as seen here:
You can edit your z-index values under Display Options in the Popup Editor.